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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 _get_network_vswitch_map_by_port_id(self, port_id):
 """Get the vswitch name for the received port id."""

        for network_id, vswitch in six.iteritems(self._network_vswitch_map):
            if port_id in vswitch['ports']:
                return (network_id, vswitch)

        # If the port was not found, just return (None, None)
        return (None, None)