Fix "target" attribute calls via six

src/sugar3/dispatch/dispatcher.py

@@ -12,7 +12,7 @@ WEAKREF_TYPES = (weakref.ReferenceType, saferef.BoundMethodWeakref)
 
 
 def _make_id(target):
-    if hasattr(target, 'im_func'):
+    if hasattr(target, 'im_func') or hasattr(target, '__func__'):
         return (id(im_self(target)), id(im_func(target)))
     return id(target)
 

src/sugar3/dispatch/saferef.py

@@ -21,13 +21,19 @@ def safeRef(target, onDelete=None):
         goes out of scope with the reference object, (either a
         weakref or a BoundMethodWeakref) as argument.
     """
-    if hasattr(target, 'im_self'):
+    if hasattr(target, 'im_self') or hasattr(target, '__self__'):
         if im_self(target) is not None:
             # Turn a bound method into a BoundMethodWeakref instance.
             # Keep track of these instances for lookup by disconnect().
-            assert hasattr(target, 'im_func'), \
-                "safeRef target %r has im_self, but no im_func, " \
-                "don't know how to create reference" % (target,)
+            if six.PY2:
+                assert hasattr(target, 'im_func'), \
+                    "safeRef target %r has im_self, but no im_func, " \
+                    "don't know how to create reference" % (target,)
+            else:
+                assert hasattr(target, '__func__'), \
+                    "safeRef target %r has __self__, but no __func__, " \
+                    "don't know how to create reference" % (target,)
+
             reference = get_bound_method_weakref(
                 target=target,
                 onDelete=onDelete