code: def assertCallerError(self, expected_arg0, callable_obj, *args, **kwargs):
          
          try:
              callable_obj(*args, **kwargs)
              self.fail('Expected AssertionError, but no exception raised')
          except AssertionError, exc:
              self.assertEqual(exc.args[0], expected_arg0)
          except Exception, exc:
              self.fail('Expected AssertionError, but got %s' % repr(exc))
docs: Assert that a callable raises an AssertionError with a particular argument.
  
          :param expected_arg0: The expected value for the AssertionError instance's first argument
                                (i.e., instance.args[0]).