diff --git a/Lib/lib-tk/Tkinter.py b/Lib/lib-tk/Tkinter.py
index 3f69bab..7b116d9 100644
--- a/Lib/lib-tk/Tkinter.py
+++ b/Lib/lib-tk/Tkinter.py
@@ -1577,7 +1577,7 @@
         """Bind function FUNC to command NAME for this widget.
         Return the function bound to NAME if None is given. NAME could be
         e.g. "WM_SAVE_YOURSELF" or "WM_DELETE_WINDOW"."""
-        if callable(func):
+        if hasattr(func, '__call__'):
             command = self._register(func)
         else:
             command = func