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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def assert_called_once_with(_mock_self, *args, **kwargs):
 """assert that the mock was called exactly once and with the specified arguments."""

        self = _mock_self
        if not self.call_count == 1:
            msg = ("Expected '%s' to be called once. Called %s times." %
                   (self._mock_name or 'mock', self.call_count))
            raise AssertionError(msg)
        return self.assert_called_with(*args, **kwargs)