complete mypy transformation

1 files changed, 20 insertions, 7 deletions

diff --git a/src/setuptools_scm/hacks.py b/src/setuptools_scm/hacks.py
index 3108de8..259bab2 100644
--- a/src/setuptools_scm/hacks.py
+++ b/src/setuptools_scm/hacks.py
@@ -1,33 +1,45 @@
 import os
+from typing import Optional
 
+from . import _types as _t
+from .config import Configuration
 from .utils import data_from_mime
 from .utils import trace
 from .version import meta
+from .version import ScmVersion
 from .version import tag_to_version
 
+_UNKNOWN = "UNKNOWN"
 
-def parse_pkginfo(root, config=None):
+
+def parse_pkginfo(
+    root: _t.PathT, config: Optional[Configuration] = None
+) -> Optional[ScmVersion]:
 
     pkginfo = os.path.join(root, "PKG-INFO")
     trace("pkginfo", pkginfo)
     data = data_from_mime(pkginfo)
-    version = data.get("Version")
-    if version != "UNKNOWN":
+    version = data.get("Version", _UNKNOWN)
+    if version != _UNKNOWN:
         return meta(version, preformatted=True, config=config)
+    else:
+        return None
 
 
-def parse_pip_egg_info(root, config=None):
+def parse_pip_egg_info(
+    root: _t.PathT, config: Optional[Configuration] = None
+) -> Optional[ScmVersion]:
     pipdir = os.path.join(root, "pip-egg-info")
     if not os.path.isdir(pipdir):
-        return
+        return None
     items = os.listdir(pipdir)
     trace("pip-egg-info", pipdir, items)
     if not items:
-        return
+        return None
     return parse_pkginfo(os.path.join(pipdir, items[0]), config=config)
 
 
-def fallback_version(root, config=None):
+def fallback_version(root: _t.PathT, config: Configuration) -> Optional[ScmVersion]:
     if config.parentdir_prefix_version is not None:
         _, parent_name = os.path.split(os.path.abspath(root))
         if parent_name.startswith(config.parentdir_prefix_version):
@@ -39,3 +51,4 @@ def fallback_version(root, config=None):
     if config.fallback_version is not None:
         trace("FALLBACK")
         return meta(config.fallback_version, preformatted=True, config=config)
+    return None