def _get_vswitch_for_physical_network(self, phys_network_name):
        """Get the vswitch name for the received network name."""
        for pattern in self._physical_network_mappings:
            if phys_network_name is None:
                phys_network_name = ''
            if re.match(pattern, phys_network_name):
                return self._physical_network_mappings[pattern]
Get the vswitch name for the received network name.