Fix typo when creating exception

Summary: As title

Reviewed By: deathowl

Differential Revision: D54228298

fbshipit-source-id: 1916d0da1ca302c0b736a859415c7db4a1049408

testslide/mock_callable.py

@@ -737,7 +737,7 @@ def _validate_patch(
                 )
             if inspect.isclass(original_callable):
                 raise ValueError(
-                    f"{name}() can not be used with with classes: "
+                    f"{name}() can not be used with classes: "
                     f"{repr(original_callable)}. Perhaps you want to use "
                     "mock_constructor() instead."
                 )