docs: 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]