human
Complete this python program:
def _AddClearExtensionMethod(cls):
assistant
#Here is the Python program you requested.

    """Helper for _AddMessageMethods().
    """
    def ClearExtension(self, extension_handle):
        _VerifyExtensionHandle(self, extension_handle)
        if (extension_handle in self._fields):
            del self._fields[extension_handle]
        self._Modified()
    cls.ClearExtension = ClearExtension