Deprecate support for Python 3.6 and remove dependency on attrs (#1257)

* Start deprecation of Python 3.6

* Removed dependency on attrs and replaced with dataclasses

* Fix typing

* Added comments to assist with dropping support of Python versions in the future.

---------

Co-authored-by: Kevin Van Brunt <kmvanbrunt@gmail.com>

35 files changed, 89 insertions, 120 deletions

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 8e3596bc..abd05ccd 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -46,9 +46,8 @@ The tables below list all prerequisites along with the minimum required version
 #### Prerequisites to run cmd2 applications
 
 | Prerequisite                                        | Minimum Version |
-| --------------------------------------------------- | --------------- |
-| [python](https://www.python.org/downloads/)         | `3.6`           |
-| [attrs](https://github.com/python-attrs/attrs)      | `16.3`          |
+| --------------------------------------------------- |-----------------|
+| [python](https://www.python.org/downloads/)         | `3.7`           |
 | [pyperclip](https://github.com/asweigart/pyperclip) | `1.6`           |
 | [setuptools](https://pypi.org/project/setuptools/)  | `34.4`          |
 | [wcwidth](https://pypi.python.org/pypi/wcwidth)     | `0.1.7`         |
diff --git a/.github/workflows/doc.yml b/.github/workflows/doc.yml
index 70bd661b..48e6b4a7 100644
--- a/.github/workflows/doc.yml
+++ b/.github/workflows/doc.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.10"]
+        python-version: ["3.11"]
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
index 6f0454d8..8c8ecb98 100644
--- a/.github/workflows/format.yml
+++ b/.github/workflows/format.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.10"]
+        python-version: ["3.11"]
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 6b567238..e36f05d7 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.10"]
+        python-version: ["3.11"]
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/.github/workflows/mypy.yml b/.github/workflows/mypy.yml
index 6a4d0533..474e1137 100644
--- a/.github/workflows/mypy.yml
+++ b/.github/workflows/mypy.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.10"]
+        python-version: ["3.11"]
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/.gitignore b/.gitignore
index 1fdfc6a5..11b71aa3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -39,4 +39,7 @@ Pipfile.lock
 .venv
 
 # Commitizen configuration
-.cz.toml
\ No newline at end of file
+.cz.toml
+
+# pyenv version file
+.python-version
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c7d52a49..57e04405 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 2.5.0 (TBD)
+* Breaking Change
+  * `cmd2` 2.5 supports Python 3.7+ (removed support for Python 3.6)
+* Enhancements
+  * Removed dependency on `attrs` and replaced with [dataclasses](https://docs.python.org/3/library/dataclasses.html)
+
 ## 2.4.3 (January 27, 2023)
 * Bug Fixes
   * Fixed ValueError caused when passing `Cmd.columnize()` strings wider than `display_width`.
diff --git a/Pipfile b/Pipfile
index f0e94a8b..fbf399ad 100644
--- a/Pipfile
+++ b/Pipfile
@@ -4,7 +4,6 @@ url = "https://pypi.org/simple"
 verify_ssl = true
 
 [packages]
-attrs = ">=16.3.0"
 pyperclip = ">=1.6"
 setuptools = ">=34.4"
 wcwidth = ">=0.1.7"
diff --git a/README.md b/README.md
index dbf7af1c..09e083df 100755
--- a/README.md
+++ b/README.md
@@ -78,7 +78,7 @@ On all operating systems, the latest stable version of `cmd2` can be installed u
 pip install -U cmd2
 ```
 
-cmd2 works with Python 3.6+ on Windows, macOS, and Linux. It is pure Python code with few 3rd-party dependencies.
+cmd2 works with Python 3.7+ on Windows, macOS, and Linux. It is pure Python code with few 3rd-party dependencies.
 
 For information on other installation options, see
 [Installation Instructions](https://cmd2.readthedocs.io/en/latest/overview/installation.html) in the cmd2
diff --git a/cmd2/argparse_completer.py b/cmd2/argparse_completer.py
index 09ec2255..88be8b52 100644
--- a/cmd2/argparse_completer.py
+++ b/cmd2/argparse_completer.py
@@ -273,10 +273,8 @@ class ArgparseCompleter:
             # Check if this action is in a mutually exclusive group
             for group in self._parser._mutually_exclusive_groups:
                 if arg_action in group._group_actions:
-
                     # Check if the group this action belongs to has already been completed
                     if group in completed_mutex_groups:
-
                         # If this is the action that completed the group, then there is no error
                         # since it's allowed to appear on the command line more than once.
                         completer_action = completed_mutex_groups[group]
@@ -307,7 +305,6 @@ class ArgparseCompleter:
         # Parse all but the last token
         #############################################################################################
         for token_index, token in enumerate(tokens[:-1]):
-
             # If we're in a positional REMAINDER arg, force all future tokens to go to that
             if pos_arg_state is not None and pos_arg_state.is_remainder:
                 consume_argument(pos_arg_state)
@@ -339,7 +336,6 @@ class ArgparseCompleter:
 
             # Check the format of the current token to see if it can be an argument's value
             if _looks_like_flag(token, self._parser) and not skip_remaining_flags:
-
                 # Check if there is an unfinished flag
                 if (
                     flag_arg_state is not None
@@ -484,7 +480,6 @@ class ArgparseCompleter:
 
         # Otherwise check if we have a positional to complete
         elif pos_arg_state is not None or remaining_positionals:
-
             # If we aren't current tracking a positional, then get the next positional arg to handle this token
             if pos_arg_state is None:
                 action = remaining_positionals.popleft()
diff --git a/cmd2/argparse_custom.py b/cmd2/argparse_custom.py
index a8ad1ebd..c2e98b75 100644
--- a/cmd2/argparse_custom.py
+++ b/cmd2/argparse_custom.py
@@ -276,6 +276,7 @@ try:
         runtime_checkable,
     )
 except ImportError:
+    # Remove these imports when we no longer support Python 3.7
     from typing_extensions import (  # type: ignore[assignment]
         Protocol,
         runtime_checkable,
@@ -807,7 +808,6 @@ def _add_argument_wrapper(
         nargs_adjusted: Union[int, str, Tuple[int], Tuple[int, int], Tuple[int, float], None]
         # Check if nargs was given as a range
         if isinstance(nargs, tuple):
-
             # Handle 1-item tuple by setting max to INFINITY
             if len(nargs) == 1:
                 nargs = (nargs[0], constants.INFINITY)
@@ -1032,6 +1032,7 @@ setattr(argparse.ArgumentParser, '_check_value', _ArgumentParser_check_value)
 # Patch argparse._SubParsersAction to add remove_parser function
 ############################################################################################################
 
+
 # noinspection PyPep8Naming,PyProtectedMember
 def _SubParsersAction_remove_parser(self: argparse._SubParsersAction, name: str) -> None:  # type: ignore
     """
@@ -1123,7 +1124,6 @@ class Cmd2HelpFormatter(argparse.RawTextHelpFormatter):
             # wrap the usage parts if it's too long
             text_width = self._width - self._current_indent
             if len(prefix) + len(usage) > text_width:
-
                 # Begin cmd2 customization
 
                 # break usage into wrappable parts
diff --git a/cmd2/cmd2.py b/cmd2/cmd2.py
index 6cd8b950..97cfb77d 100644
--- a/cmd2/cmd2.py
+++ b/cmd2/cmd2.py
@@ -155,13 +155,11 @@ else:
     orig_rl_delims = readline.get_completer_delims()
 
     if rl_type == RlType.PYREADLINE:
-
         # Save the original pyreadline3 display completion function since we need to override it and restore it
         # noinspection PyProtectedMember,PyUnresolvedReferences
         orig_pyreadline_display = readline.rl.mode._display_completions
 
     elif rl_type == RlType.GNU:
-
         # Get the readline lib so we can make changes to it
         import ctypes
 
@@ -1498,7 +1496,6 @@ class Cmd(cmd.Cmd):
 
         # Used to complete ~ and ~user strings
         def complete_users() -> List[str]:
-
             users = []
 
             # Windows lacks the pwd module so we can't get a list of users.
@@ -1516,10 +1513,8 @@ class Cmd(cmd.Cmd):
 
                 # Iterate through a list of users from the password database
                 for cur_pw in pwd.getpwall():
-
                     # Check if the user has an existing home dir
                     if os.path.isdir(cur_pw.pw_dir):
-
                         # Add a ~ to the user to match against text
                         cur_user = '~' + cur_pw.pw_name
                         if cur_user.startswith(text):
@@ -1605,7 +1600,6 @@ class Cmd(cmd.Cmd):
 
             # Build display_matches and add a slash to directories
             for index, cur_match in enumerate(matches):
-
                 # Display only the basename of this path in the tab completion suggestions
                 self.display_matches.append(os.path.basename(cur_match))
 
@@ -1674,7 +1668,6 @@ class Cmd(cmd.Cmd):
 
         # Must at least have the command
         if len(raw_tokens) > 1:
-
             # True when command line contains any redirection tokens
             has_redirection = False
 
@@ -1766,7 +1759,6 @@ class Cmd(cmd.Cmd):
         :param longest_match_length: longest printed length of the matches
         """
         if rl_type == RlType.GNU:
-
             # Print hint if one exists and we are supposed to display it
             hint_printed = False
             if self.always_show_hint and self.completion_hint:
@@ -1826,7 +1818,6 @@ class Cmd(cmd.Cmd):
         :param matches: the tab completion matches to display
         """
         if rl_type == RlType.PYREADLINE:
-
             # Print hint if one exists and we are supposed to display it
             hint_printed = False
             if self.always_show_hint and self.completion_hint:
@@ -1980,7 +1971,6 @@ class Cmd(cmd.Cmd):
 
         # Check if the token being completed has an opening quote
         if raw_completion_token and raw_completion_token[0] in constants.QUOTES:
-
             # Since the token is still being completed, we know the opening quote is unclosed.
             # Save the quote so we can add a matching closing quote later.
             completion_token_quote = raw_completion_token[0]
@@ -2005,7 +1995,6 @@ class Cmd(cmd.Cmd):
         self.completion_matches = self._redirect_complete(text, line, begidx, endidx, completer_func)
 
         if self.completion_matches:
-
             # Eliminate duplicates
             self.completion_matches = utils.remove_duplicates(self.completion_matches)
             self.display_matches = utils.remove_duplicates(self.display_matches)
@@ -2020,7 +2009,6 @@ class Cmd(cmd.Cmd):
 
             # Check if we need to add an opening quote
             if not completion_token_quote:
-
                 add_quote = False
 
                 # This is the tab completion text that will appear on the command line.
@@ -2103,7 +2091,7 @@ class Cmd(cmd.Cmd):
                 # from text and update the indexes. This only applies if we are at the beginning of the command line.
                 shortcut_to_restore = ''
                 if begidx == 0 and custom_settings is None:
-                    for (shortcut, _) in self.statement_parser.shortcuts:
+                    for shortcut, _ in self.statement_parser.shortcuts:
                         if text.startswith(shortcut):
                             # Save the shortcut to restore later
                             shortcut_to_restore = shortcut
@@ -3066,7 +3054,6 @@ class Cmd(cmd.Cmd):
         readline_settings = _SavedReadlineSettings()
 
         if self._completion_supported():
-
             # Set up readline for our tab completion needs
             if rl_type == RlType.GNU:
                 # GNU readline automatically adds a closing quote if the text being completed has an opening quote.
@@ -3100,7 +3087,6 @@ class Cmd(cmd.Cmd):
         :param readline_settings: the readline settings to restore
         """
         if self._completion_supported():
-
             # Restore what we changed in readline
             readline.set_completer(readline_settings.completer)
             readline.set_completer_delims(readline_settings.delims)
@@ -3881,7 +3867,7 @@ class Cmd(cmd.Cmd):
                     fulloptions.append((opt[0], opt[1]))
                 except IndexError:
                     fulloptions.append((opt[0], opt[0]))
-        for (idx, (_, text)) in enumerate(fulloptions):
+        for idx, (_, text) in enumerate(fulloptions):
             self.poutput('  %2d. %s' % (idx + 1, text))
 
         while True:
@@ -5035,7 +5021,6 @@ class Cmd(cmd.Cmd):
 
         # Sanity check that can't fail if self.terminal_lock was acquired before calling this function
         if self.terminal_lock.acquire(blocking=False):
-
             # Windows terminals tend to flicker when we redraw the prompt and input lines.
             # To reduce how often this occurs, only update terminal if there are changes.
             update_terminal = False
diff --git a/cmd2/history.py b/cmd2/history.py
index df3c1255..a7d6baff 100644
--- a/cmd2/history.py
+++ b/cmd2/history.py
@@ -8,6 +8,9 @@ import re
 from collections import (
     OrderedDict,
 )
+from dataclasses import (
+    dataclass,
+)
 from typing import (
     Any,
     Callable,
@@ -19,8 +22,6 @@ from typing import (
     overload,
 )
 
-import attr
-
 from . import (
     utils,
 )
@@ -29,7 +30,7 @@ from .parsing import (
 )
 
 
-@attr.s(auto_attribs=True, frozen=True)
+@dataclass(frozen=True)
 class HistoryItem:
     """Class used to represent one command in the history list"""
 
@@ -39,10 +40,10 @@ class HistoryItem:
     # Used in JSON dictionaries
     _statement_field = 'statement'
 
-    statement: Statement = attr.ib(default=None, validator=attr.validators.instance_of(Statement))
+    statement: Statement
 
     def __str__(self) -> str:
-        """A convenient human readable representation of the history item"""
+        """A convenient human-readable representation of the history item"""
         return self.statement.raw
 
     @property
@@ -90,7 +91,7 @@ class HistoryItem:
                 if self.statement.multiline_command:
                     # This is an approximation and not meant to be a perfect piecing together of lines.
                     # All newlines will be converted to spaces, including the ones in quoted strings that
-                    # are considered literals. Also if the final line starts with a terminator, then the
+                    # are considered literals. Also, if the final line starts with a terminator, then the
                     # terminator will have an extra space before it in the 1 line version.
                     ret_str = ret_str.replace('\n', ' ')
 
diff --git a/cmd2/parsing.py b/cmd2/parsing.py
index 9069cea2..fc28b634 100755
--- a/cmd2/parsing.py
+++ b/cmd2/parsing.py
@@ -4,6 +4,10 @@
 
 import re
 import shlex
+from dataclasses import (
+    dataclass,
+    field,
+)
 from typing import (
     Any,
     Dict,
@@ -14,8 +18,6 @@ from typing import (
     Union,
 )
 
-import attr
-
 from . import (
     constants,
     utils,
@@ -36,7 +38,7 @@ def shlex_split(str_to_split: str) -> List[str]:
     return shlex.split(str_to_split, comments=False, posix=False)
 
 
-@attr.s(auto_attribs=True, frozen=True)
+@dataclass(frozen=True)
 class MacroArg:
     """
     Information used to replace or unescape arguments in a macro value when the macro is resolved
@@ -45,15 +47,15 @@ class MacroArg:
     """
 
     # The starting index of this argument in the macro value
-    start_index: int = attr.ib(validator=attr.validators.instance_of(int))
+    start_index: int
 
     # The number string that appears between the braces
     # This is a string instead of an int because we support unicode digits and must be able
     # to reproduce this string later
-    number_str: str = attr.ib(validator=attr.validators.instance_of(str))
+    number_str: str
 
     # Tells if this argument is escaped and therefore needs to be unescaped
-    is_escaped: bool = attr.ib(validator=attr.validators.instance_of(bool))
+    is_escaped: bool
 
     # Pattern used to find normal argument
     # Digits surrounded by exactly 1 brace on a side and 1 or more braces on the opposite side
@@ -69,24 +71,24 @@ class MacroArg:
     digit_pattern = re.compile(r'\d+')
 
 
-@attr.s(auto_attribs=True, frozen=True)
+@dataclass(frozen=True)
 class Macro:
     """Defines a cmd2 macro"""
 
     # Name of the macro
-    name: str = attr.ib(validator=attr.validators.instance_of(str))
+    name: str
 
     # The string the macro resolves to
-    value: str = attr.ib(validator=attr.validators.instance_of(str))
+    value: str
 
     # The minimum number of args the user has to pass to this macro
-    minimum_arg_count: int = attr.ib(validator=attr.validators.instance_of(int))
+    minimum_arg_count: int
 
     # Used to fill in argument placeholders in the macro
-    arg_list: List[MacroArg] = attr.ib(default=attr.Factory(list), validator=attr.validators.instance_of(list))
+    arg_list: List[MacroArg] = field(default_factory=list)
 
 
-@attr.s(auto_attribs=True, frozen=True)
+@dataclass(frozen=True)
 class Statement(str):  # type: ignore[override]
     """String subclass with additional attributes to store the results of parsing.
 
@@ -118,34 +120,34 @@ class Statement(str):  # type: ignore[override]
     """
 
     # the arguments, but not the command, nor the output redirection clauses.
-    args: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    args: str = ''
 
     # string containing exactly what we input by the user
-    raw: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    raw: str = ''
 
     # the command, i.e. the first whitespace delimited word
-    command: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    command: str = ''
 
     # list of arguments to the command, not including any output redirection or terminators; quoted args remain quoted
-    arg_list: List[str] = attr.ib(default=attr.Factory(list), validator=attr.validators.instance_of(list))
+    arg_list: List[str] = field(default_factory=list)
 
     # if the command is a multiline command, the name of the command, otherwise empty
-    multiline_command: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    multiline_command: str = ''
 
     # the character which terminated the multiline command, if there was one
-    terminator: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    terminator: str = ''
 
     # characters appearing after the terminator but before output redirection, if any
-    suffix: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    suffix: str = ''
 
     # if output was piped to a shell command, the shell command as a string
-    pipe_to: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    pipe_to: str = ''
 
     # if output was redirected, the redirection token, i.e. '>>'
-    output: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    output: str = ''
 
     # if output was redirected, the destination file token (quotes preserved)
-    output_to: str = attr.ib(default='', validator=attr.validators.instance_of(str))
+    output_to: str = ''
 
     # Used in JSON dictionaries
     _args_field = 'args'
@@ -156,7 +158,7 @@ class Statement(str):  # type: ignore[override]
         We must override __new__ because we are subclassing `str` which is
         immutable and takes a different number of arguments as Statement.
 
-        NOTE:  attrs takes care of initializing other members in the __init__ it
+        NOTE:  @dataclass takes care of initializing other members in the __init__ it
         generates.
         """
         stmt = super().__new__(cls, value)
@@ -348,7 +350,7 @@ class StatementParser:
             return False, 'cannot start with the comment character'
 
         if not is_subcommand:
-            for (shortcut, _) in self.shortcuts:
+            for shortcut, _ in self.shortcuts:
                 if word.startswith(shortcut):
                     # Build an error string with all shortcuts listed
                     errmsg = 'cannot start with a shortcut: '
@@ -481,7 +483,6 @@ class StatementParser:
 
         # Check if output should be piped to a shell command
         if pipe_index < redir_index and pipe_index < append_index:
-
             # Get the tokens for the pipe command and expand ~ where needed
             pipe_to_tokens = tokens[pipe_index + 1 :]
             utils.expand_user_in_tokens(pipe_to_tokens)
@@ -656,7 +657,7 @@ class StatementParser:
                     keep_expanding = bool(remaining_aliases)
 
         # expand shortcuts
-        for (shortcut, expansion) in self.shortcuts:
+        for shortcut, expansion in self.shortcuts:
             if line.startswith(shortcut):
                 # If the next character after the shortcut isn't a space, then insert one
                 shortcut_len = len(shortcut)
@@ -701,7 +702,6 @@ class StatementParser:
         punctuated_tokens = []
 
         for cur_initial_token in tokens:
-
             # Save tokens up to 1 character in length or quoted tokens. No need to parse these.
             if len(cur_initial_token) <= 1 or cur_initial_token[0] in constants.QUOTES:
                 punctuated_tokens.append(cur_initial_token)
@@ -716,7 +716,6 @@ class StatementParser:
 
             while True:
                 if cur_char not in punctuation:
-
                     # Keep appending to new_token until we hit a punctuation char
                     while cur_char not in punctuation:
                         new_token += cur_char
diff --git a/cmd2/plugin.py b/cmd2/plugin.py
index f9f5c573..affe2421 100644
--- a/cmd2/plugin.py
+++ b/cmd2/plugin.py
@@ -1,18 +1,19 @@
 #
 # coding=utf-8
 """Classes for the cmd2 plugin system"""
+from dataclasses import (
+    dataclass,
+)
 from typing import (
     Optional,
 )
 
-import attr
-
 from .parsing import (
     Statement,
 )
 
 
-@attr.s(auto_attribs=True)
+@dataclass
 class PostparsingData:
     """Data class containing information passed to postparsing hook methods"""
 
@@ -20,14 +21,14 @@ class PostparsingData:
     statement: Statement
 
 
-@attr.s(auto_attribs=True)
+@dataclass
 class PrecommandData:
     """Data class containing information passed to precommand hook methods"""
 
     statement: Statement
 
 
-@attr.s(auto_attribs=True)
+@dataclass
 class PostcommandData:
     """Data class containing information passed to postcommand hook methods"""
 
@@ -35,7 +36,7 @@ class PostcommandData:
     statement: Statement
 
 
-@attr.s(auto_attribs=True)
+@dataclass
 class CommandFinalizationData:
     """Data class containing information passed to command finalization hook methods"""
 
diff --git a/cmd2/transcript.py b/cmd2/transcript.py
index 83ede932..a38c1902 100644
--- a/cmd2/transcript.py
+++ b/cmd2/transcript.py
@@ -60,7 +60,7 @@ class Cmd2TestCase(unittest.TestCase):
     def runTest(self) -> None:  # was testall
         if self.cmdapp:
             its = sorted(self.transcripts.items())
-            for (fname, transcript) in its:
+            for fname, transcript in its:
                 self._test_transcript(fname, transcript)
 
     def _fetchTranscripts(self) -> None:
diff --git a/docs/features/transcripts.rst b/docs/features/transcripts.rst
index fa6d9cb3..9bab8996 100644
--- a/docs/features/transcripts.rst
+++ b/docs/features/transcripts.rst
@@ -127,8 +127,8 @@ If your output has slashes in it, you will need to escape those slashes so the
 stuff between them is not interpred as a regular expression. In this
 transcript::
 
-   (Cmd) say cd /usr/local/lib/python3.6/site-packages
-   /usr/local/lib/python3.6/site-packages
+   (Cmd) say cd /usr/local/lib/python3.11/site-packages
+   /usr/local/lib/python3.11/site-packages
 
 the output contains slashes. The text between the first slash and the second
 slash, will be interpreted as a regular expression, and those two slashes will
@@ -136,8 +136,8 @@ not be included in the comparison. When replayed, this transcript would
 therefore fail. To fix it, we could either write a regular expression to match
 the path instead of specifying it verbatim, or we can escape the slashes::
 
-   (Cmd) say cd /usr/local/lib/python3.6/site-packages
-   \/usr\/local\/lib\/python3.6\/site-packages
+   (Cmd) say cd /usr/local/lib/python3.11/site-packages
+   \/usr\/local\/lib\/python3.11\/site-packages
 
 .. warning::
 
diff --git a/docs/overview/installation.rst b/docs/overview/installation.rst
index a98fef52..743e0aca 100644
--- a/docs/overview/installation.rst
+++ b/docs/overview/installation.rst
@@ -7,7 +7,7 @@ Installation Instructions
 .. _setuptools: https://pypi.org/project/setuptools
 .. _PyPI: https://pypi.org
 
-``cmd2`` works on Linux, macOS, and Windows. It requires Python 3.6 or
+``cmd2`` works on Linux, macOS, and Windows. It requires Python 3.7 or
 higher, pip_, and setuptools_. If you've got all that, then you can just:
 
 .. code-block:: shell
@@ -30,7 +30,7 @@ higher, pip_, and setuptools_. If you've got all that, then you can just:
 Prerequisites
 -------------
 
-If you have Python 3 >=3.6 installed from `python.org
+If you have Python 3 >=3.7 installed from `python.org
 <https://www.python.org>`_, you will already have pip_ and setuptools_, but may
 need to upgrade to the latest versions:
 
diff --git a/examples/async_printing.py b/examples/async_printing.py
index 15a4445e..6ff3a262 100755
--- a/examples/async_printing.py
+++ b/examples/async_printing.py
@@ -176,7 +176,6 @@ class AlerterApp(cmd2.Cmd):
             # Always acquire terminal_lock before printing alerts or updating the prompt
             # To keep the app responsive, do not block on this call
             if self.terminal_lock.acquire(blocking=False):
-
                 # Get any alerts that need to be printed
                 alert_str = self._generate_alert_str()
 
diff --git a/examples/scripts/save_help_text.py b/examples/scripts/save_help_text.py
index ad028395..b8ba9624 100644
--- a/examples/scripts/save_help_text.py
+++ b/examples/scripts/save_help_text.py
@@ -22,7 +22,6 @@ def get_sub_commands(parser: argparse.ArgumentParser) -> List[str]:
 
     # Check if this is parser has subcommands
     if parser is not None and parser._subparsers is not None:
-
         # Find the _SubParsersAction for the subcommands of this parser
         for action in parser._subparsers._actions:
             if isinstance(action, argparse._SubParsersAction):
diff --git a/noxfile.py b/noxfile.py
index 14b4d5a0..f7a705fb 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -1,7 +1,7 @@
 import nox
 
 
-@nox.session(python=['3.10'])
+@nox.session(python=['3.11'])
 def docs(session):
     session.install(
         'sphinx',
@@ -41,7 +41,7 @@ def tests(session, plugin):
         )
 
 
-@nox.session(python=['3.8', '3.9', '3.10'])
+@nox.session(python=['3.8', '3.9', '3.10', '3.11'])
 @nox.parametrize('step', ['mypy', 'flake8'])
 def validate(session, step):
     session.install('invoke', './[validate]')
diff --git a/plugins/ext_test/build-pyenvs.sh b/plugins/ext_test/build-pyenvs.sh
index d64e11bd..572db568 100644
--- a/plugins/ext_test/build-pyenvs.sh
+++ b/plugins/ext_test/build-pyenvs.sh
@@ -23,7 +23,7 @@
 # virtualenvs will be added to '.python-version'. Feel free to modify
 # this list, but note that this script intentionally won't install
 # dev, rc, or beta python releases
-declare -a pythons=("3.7" "3.6" "3.8" "3.9")
+declare -a pythons=("3.7" "3.8" "3.9", "3.10", "3.11")
 
 # function to find the latest patch of a minor version of python
 function find_latest_version {
diff --git a/plugins/ext_test/cmd2_ext_test/__init__.py b/plugins/ext_test/cmd2_ext_test/__init__.py
index c17a329a..b30c949d 100644
--- a/plugins/ext_test/cmd2_ext_test/__init__.py
+++ b/plugins/ext_test/cmd2_ext_test/__init__.py
@@ -9,7 +9,7 @@ try:
     # For python 3.8 and later
     import importlib.metadata as importlib_metadata
 except ImportError:  # pragma: no cover
-    # For everyone else
+    # Remove this import when we no longer support Python 3.7
     # MyPy Issue # 1153 causes a spurious error that must be ignored
     import importlib_metadata  # type: ignore
 
diff --git a/plugins/ext_test/noxfile.py b/plugins/ext_test/noxfile.py
index 75eab841..9872e193 100644
--- a/plugins/ext_test/noxfile.py
+++ b/plugins/ext_test/noxfile.py
@@ -1,7 +1,7 @@
 import nox
 
 
-@nox.session(python=['3.6', '3.7', '3.8', '3.9'])
+@nox.session(python=['3.7', '3.8', '3.9', '3.10', '3.11'])
 def tests(session):
     session.install('invoke', './[test]')
     session.run('invoke', 'pytest', '--junit', '--no-pty')
diff --git a/plugins/ext_test/setup.py b/plugins/ext_test/setup.py
index 06e7827d..644d2677 100644
--- a/plugins/ext_test/setup.py
+++ b/plugins/ext_test/setup.py
@@ -33,7 +33,7 @@ setuptools.setup(
     license='MIT',
     package_data=PACKAGE_DATA,
     packages=['cmd2_ext_test'],
-    python_requires='>=3.6',
+    python_requires='>=3.7',
     install_requires=['cmd2 >= 2, <3'],
     setup_requires=['setuptools >= 42', 'setuptools_scm >= 3.4'],
     classifiers=[
@@ -43,11 +43,11 @@ setuptools.setup(
         'Topic :: Software Development :: Libraries :: Python Modules',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: MIT License',
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
+        'Programming Language :: Python :: 3.11',
     ],
     # dependencies for development and testing
     # $ pip install -e .[dev]
diff --git a/plugins/ext_test/tasks.py b/plugins/ext_test/tasks.py
index 757dfe79..6370af0c 100644
--- a/plugins/ext_test/tasks.py
+++ b/plugins/ext_test/tasks.py
@@ -17,6 +17,7 @@ import invoke
 TASK_ROOT = pathlib.Path(__file__).resolve().parent
 TASK_ROOT_STR = str(TASK_ROOT)
 
+
 # shared function
 def rmrf(items, verbose=True):
     """Silently remove a list of directories or files"""
diff --git a/plugins/template/README.md b/plugins/template/README.md
index 509fa0c0..f7f6d057 100644
--- a/plugins/template/README.md
+++ b/plugins/template/README.md
@@ -233,8 +233,6 @@ If you prefer to create these virtualenvs by hand, do the following:
 $ cd cmd2_abbrev
 $ pyenv install 3.7.0
 $ pyenv virtualenv -p python3.7 3.7.0 cmd2-3.7
-$ pyenv install 3.6.5
-$ pyenv virtualenv -p python3.6 3.6.5 cmd2-3.6
 $ pyenv install 3.8.5
 $ pyenv virtualenv -p python3.8 3.8.5 cmd2-3.8
 $ pyenv install 3.9.0
@@ -243,7 +241,7 @@ $ pyenv virtualenv -p python3.9 3.9.0 cmd2-3.9
 
 Now set pyenv to make all three of those available at the same time:
 ```
-$ pyenv local cmd2-3.7 cmd2-3.6 cmd2-3.8 cmd2-3.9
+$ pyenv local cmd2-3.7 cmd2-3.8 cmd2-3.9
 ```
 
 Whether you ran the script, or did it by hand, you now have isolated virtualenvs
@@ -253,16 +251,10 @@ utilize.
 
 | Command     | python | virtualenv |
 | ----------- | ------ | ---------- |
-| `python`    | 3.7.0  | cmd2-3.6   |
-| `python3`   | 3.7.0  | cmd2-3.6   |
 | `python3.7` | 3.7.0  | cmd2-3.7   |
-| `python3.6` | 3.6.5  | cmd2-3.6   |
 | `python3.8` | 3.8.5  | cmd2-3.8   |
 | `python3.9` | 3.9.0  | cmd2-3.9   |
-| `pip`       | 3.7.0  | cmd2-3.6   |
-| `pip3`      | 3.7.0  | cmd2-3.6   |
 | `pip3.7`    | 3.7.0  | cmd2-3.7   |
-| `pip3.6`    | 3.6.5  | cmd2-3.6   |
 | `pip3.8`    | 3.8.5  | cmd2-3.8   |
 | `pip3.9`    | 3.9.0  | cmd2-3.9   |
 
diff --git a/plugins/template/cmd2_myplugin/__init__.py b/plugins/template/cmd2_myplugin/__init__.py
index daa20e71..394b219b 100644
--- a/plugins/template/cmd2_myplugin/__init__.py
+++ b/plugins/template/cmd2_myplugin/__init__.py
@@ -14,7 +14,7 @@ try:
     # For python 3.8 and later
     import importlib.metadata as importlib_metadata
 except ImportError:  # pragma: no cover
-    # For everyone else
+    # Remove this import when we no longer support Python 3.7
     import importlib_metadata
 try:
     __version__ = importlib_metadata.version(__name__)
diff --git a/plugins/template/setup.py b/plugins/template/setup.py
index 5fab9f06..47cc72c2 100644
--- a/plugins/template/setup.py
+++ b/plugins/template/setup.py
@@ -24,7 +24,7 @@ setuptools.setup(
     url='https://github.com/python-cmd2/cmd2-plugin-template',
     license='MIT',
     packages=['cmd2_myplugin'],
-    python_requires='>=3.6',
+    python_requires='>=3.7',
     install_requires=['cmd2 >= 2, <3'],
     setup_requires=['setuptools_scm'],
     classifiers=[
@@ -34,7 +34,6 @@ setuptools.setup(
         'Topic :: Software Development :: Libraries :: Python Modules',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: MIT License',
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
diff --git a/setup.py b/setup.py
index 591ba9f8..b5724dd4 100755
--- a/setup.py
+++ b/setup.py
@@ -28,11 +28,11 @@ Intended Audience :: System Administrators
 License :: OSI Approved :: MIT License
 Programming Language :: Python
 Programming Language :: Python :: 3
-Programming Language :: Python :: 3.6
 Programming Language :: Python :: 3.7
 Programming Language :: Python :: 3.8
 Programming Language :: Python :: 3.9
 Programming Language :: Python :: 3.10
+Programming Language :: Python :: 3.11
 Programming Language :: Python :: Implementation :: CPython
 Topic :: Software Development :: Libraries :: Python Modules
 """.splitlines(),
@@ -43,7 +43,6 @@ Topic :: Software Development :: Libraries :: Python Modules
 SETUP_REQUIRES = ['setuptools >= 34.4', 'setuptools_scm >= 3.0']
 
 INSTALL_REQUIRES = [
-    'attrs >= 16.3.0',
     'importlib_metadata>=1.6.0;python_version<"3.8"',
     'pyperclip >= 1.6',
     'typing_extensions; python_version<"3.8"',
@@ -104,7 +103,7 @@ setup(
     package_data=PACKAGE_DATA,
     packages=['cmd2'],
     keywords='command prompt console cmd',
-    python_requires='>=3.6',
+    python_requires='>=3.7',
     setup_requires=SETUP_REQUIRES,
     install_requires=INSTALL_REQUIRES,
     extras_require=EXTRAS_REQUIRE,
diff --git a/tests/test_argparse_custom.py b/tests/test_argparse_custom.py
index d425baa8..36f2fce5 100644
--- a/tests/test_argparse_custom.py
+++ b/tests/test_argparse_custom.py
@@ -184,7 +184,6 @@ def test_apcustom_narg_tuple_one_base():
 
 # noinspection PyUnresolvedReferences
 def test_apcustom_narg_tuple_other_ranges():
-
     # Test range with no upper bound on max
     parser = Cmd2ArgumentParser()
     arg = parser.add_argument('arg', nargs=(2,))
diff --git a/tests/test_parsing.py b/tests/test_parsing.py
index 59b8905b..6fe67d20 100755
--- a/tests/test_parsing.py
+++ b/tests/test_parsing.py
@@ -3,7 +3,8 @@
 """
 Test the parsing logic in parsing.py
 """
-import attr
+import dataclasses
+
 import pytest
 
 import cmd2
@@ -939,9 +940,9 @@ def test_statement_is_immutable():
     assert string == statement
     assert statement.args == statement
     assert statement.raw == ''
-    with pytest.raises(attr.exceptions.FrozenInstanceError):
+    with pytest.raises(dataclasses.FrozenInstanceError):
         statement.args = 'bar'
-    with pytest.raises(attr.exceptions.FrozenInstanceError):
+    with pytest.raises(dataclasses.FrozenInstanceError):
         statement.raw = 'baz'
 
 
diff --git a/tests/test_transcript.py b/tests/test_transcript.py
index f5ca653e..39c87532 100644
--- a/tests/test_transcript.py
+++ b/tests/test_transcript.py
@@ -30,7 +30,6 @@ from .conftest import (
 
 
 class CmdLineApp(cmd2.Cmd):
-
     MUMBLES = ['like', '...', 'um', 'er', 'hmmm', 'ahh']
     MUMBLE_FIRST = ['so', 'like', 'well']
     MUMBLE_LAST = ['right?']
diff --git a/tests/test_utils.py b/tests/test_utils.py
index cfdf07b0..806cfc7d 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -7,6 +7,9 @@ import os
 import signal
 import sys
 import time
+from unittest import (
+    mock,
+)
 
 import pytest
 
@@ -18,14 +21,6 @@ from cmd2.constants import (
     HORIZONTAL_ELLIPSIS,
 )
 
-try:
-    import mock
-except ImportError:
-    from unittest import (
-        mock,
-    )
-
-
 HELLO_WORLD = 'Hello, world!'
 
 
diff --git a/tests_isolated/test_commandset/test_commandset.py b/tests_isolated/test_commandset/test_commandset.py
index 522a99e1..cfe8090d 100644
--- a/tests_isolated/test_commandset/test_commandset.py
+++ b/tests_isolated/test_commandset/test_commandset.py
@@ -186,7 +186,6 @@ def test_custom_construct_commandsets():
 
 
 def test_load_commands(command_sets_manual, capsys):
-
     # now install a command set and verify the commands are now present
     cmd_set = CommandSetA()
 
@@ -454,7 +453,6 @@ class LoadableVegetables(cmd2.CommandSet):
 
 
 def test_subcommands(command_sets_manual):
-
     base_cmds = LoadableBase(1)
     badbase_cmds = LoadableBadBase(1)
     fruit_cmds = LoadableFruits(1)