bpo-41792: Add is_typeddict function to typing.py (GH-22254)

Closes issue41792.

Also closes https://github.com/python/typing/issues/751.

1 files changed, 15 insertions, 0 deletions

diff --git a/Lib/typing.py b/Lib/typing.py
index 2aedbeb852..8c61bd8e08 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -103,6 +103,7 @@ __all__ = [
     'get_args',
     'get_origin',
     'get_type_hints',
+    'is_typeddict',
     'NewType',
     'no_type_check',
     'no_type_check_decorator',
@@ -1479,6 +1480,20 @@ def get_args(tp):
     return ()
 
 
+def is_typeddict(tp):
+    """Check if an annotation is a TypedDict class
+
+    For example::
+        class Film(TypedDict):
+            title: str
+            year: int
+
+        is_typeddict(Film)  # => True
+        is_typeddict(Union[list, str])  # => False
+    """
+    return isinstance(tp, _TypedDictMeta)
+
+
 def no_type_check(arg):
     """Decorator to indicate that annotations are not type hints.