code: def set_mappings(self, mappings):
          
  
          for source, destination in mappings.items():
              if not isinstance(source, str) or not isinstance(destination, str):
                  raise DynamipsError("Invalid Frame-Relay mappings")
              source_port, source_dlci = map(int, source.split(':'))
              destination_port, destination_dlci = map(int, destination.split(':'))
              if self.has_port(destination_port):
                  if (source_port, source_dlci) not in self._active_mappings and (destination_port, destination_dlci) not in self._active_mappings:
                      log.info('Frame Relay switch "{name}" [{id}]: mapping VC between port {source_port} DLCI {source_dlci} and port {destination_port} DLCI {destination_dlci}'.format(name=self._name,
                                                                                                                                                                                         id=self._id,
                                                                                                                                                                                         source_port=source_port,
                                                                                                                                                                                         source_dlci=source_dlci,
                                                                                                                                                                                         destination_port=destination_port,
                                                                                                                                                                                         destination_dlci=destination_dlci))
  
                      yield from self.map_vc(source_port, source_dlci, destination_port, destination_dlci)
                      yield from self.map_vc(destination_port, destination_dlci, source_port, source_dlci)
docs: Applies VC mappings
  
          :param mappings: mappings (dict)