def _invalidate_cached_client(self):
        self._cached_client = None
Returns raw email.Message instance.  Validates message first.
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/virt/ironic/client_wrapper.py/IronicClientWrapper._invalidate_cached_client--crossover with--dataset/ETHPy150Open Pylons/pyramid_mailer/pyramid_mailer/message.py/Message.to_message