gh-82406: document duck-type nature of inspect.is*function

Doc/library/inspect.rst

@@ -485,6 +485,10 @@ attributes (see :ref:`import-mod-attrs` for module attributes):
       Functions wrapped in :func:`functools.partial` now return ``True`` if the
       wrapped function is a Python generator function.
 
+   .. versionchanged:: 3.10.6
+      :term:`Duck-typed <duck-typing>` function-like objects now return
+      ``True`` if their code object has the :data:`CO_GENERATOR` flag.
+
    .. versionchanged:: 3.13
       Functions wrapped in :func:`functools.partialmethod` now return ``True``
       if the wrapped function is a Python generator function.
@@ -507,6 +511,10 @@ attributes (see :ref:`import-mod-attrs` for module attributes):
       Functions wrapped in :func:`functools.partial` now return ``True`` if the
       wrapped function is a :term:`coroutine function`.
 
+   .. versionchanged:: 3.10.6
+      :term:`Duck-typed <duck-typing>` function-like objects now return
+      ``True`` if their code object has the :data:`CO_COROUTINE` flag.
+
    .. versionchanged:: 3.12
       Sync functions marked with :func:`markcoroutinefunction` now return
       ``True``.
@@ -581,6 +589,10 @@ attributes (see :ref:`import-mod-attrs` for module attributes):
       Functions wrapped in :func:`functools.partial` now return ``True`` if the
       wrapped function is an :term:`asynchronous generator` function.
 
+   .. versionchanged:: 3.10.6
+      :term:`Duck-typed <duck-typing>` function-like objects now return
+      ``True`` if their code object has the :data:`CO_ASYNC_GENERATOR` flag.
+
    .. versionchanged:: 3.13
       Functions wrapped in :func:`functools.partialmethod` now return ``True``
       if the wrapped function is a :term:`asynchronous generator` function.

Lib/inspect.py

@@ -298,6 +298,8 @@ def _has_code_flag(f, flag):
     f = functools._unwrap_partial(f)
     if not (isfunction(f) or _signature_is_functionlike(f)):
         return False
+    # If it's a pure Python function, or an object that is duck type
+    # of a Python function (Cython and Mock functions, for instance), then:
     return bool(f.__code__.co_flags & flag)
 
 def isgeneratorfunction(obj):
@@ -2338,7 +2340,7 @@ def _signature_from_function(cls, func, skip_bound_arg=True,
             is_duck_function = True
         else:
             # If it's not a pure Python function, and not a duck type
-            # of pure function:
+            # of pure function (Cython and Mock functions, for instance), then:
             raise TypeError('{!r} is not a Python function'.format(func))
 
     s = getattr(func, "__text_signature__", None)
@@ -2531,7 +2533,7 @@ def _signature_from_callable(obj, *,
 
     if isfunction(obj) or _signature_is_functionlike(obj):
         # If it's a pure Python function, or an object that is duck type
-        # of a Python function (Cython functions, for instance), then:
+        # of a Python function (Cython and Mock functions, for instance), then:
         return _signature_from_function(sigcls, obj,
                                         skip_bound_arg=skip_bound_arg,
                                         globals=globals, locals=locals, eval_str=eval_str,