nit(twisted/consumer, is_coro): add backwards compatibility for Python 3.9-

Author: servusdei2018

fedora_messaging/twisted/consumer.py

@@ -46,9 +46,16 @@ def is_coro(
     func_or_obj: config.CallbackType,
 ) -> "TypeGuard[Callable[..., Coroutine[Any, Any, Any]]]":
     """Tests if a function is a coroutine function or a callable coroutine object."""
-    # Until Python 3.10, inspect.iscoroutinefunction() will fail to identify AsyncMocks
-    # as coroutines: https://github.com/python/cpython/issues/84753
-    # Use asyncio.iscoroutinefunction() instead.
+    # Workaround for CPython issue #84753 in Python 3.9 and older
+    # c.f.: https://github.com/python/cpython/issues/84753
+    if sys.version_info < (3, 10):
+        from unittest.mock import AsyncMock
+
+        if isinstance(func_or_obj, AsyncMock) or (
+            callable(func_or_obj) and isinstance(getattr(func_or_obj, "__call__", None), AsyncMock)
+        ):
+            return True
+
     return inspect.iscoroutinefunction(func_or_obj) or (
         callable(func_or_obj) and inspect.iscoroutinefunction(func_or_obj.__call__)  # type: ignore
     )