code: def get_extra_info(self, name, default=None):
          
          if name == 'related_address':
              return self.__inner_protocol.transport.get_extra_info('sockname')
          elif name == 'sockname':
              return self.__relayed_address
          return default
docs: Return optional transport information.
  
          - `'related_address'`: the related address
          - `'sockname'`: the relayed address