#4795 inspect.isgeneratorfunction() should return False instead of None

Lib/inspect.py

@@ -161,6 +161,7 @@ def isgeneratorfunction(object):
     if (isfunction(object) or ismethod(object)) and \
         object.func_code.co_flags & CO_GENERATOR:
         return True
+    return False
 
 def isgenerator(object):
     """Return true if the object is a generator.

Misc/NEWS

@@ -100,6 +100,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #4795: inspect.isgeneratorfunction() returns False instead of None when
+  the function is not a generator.
+
 - Issue #4702: Throwing a DistutilsPlatformError instead of IOError in case 
   no MSVC compiler is found under Windows. Original patch by Philip Jenvey.