code: def closing_address(
              self,
              participant1: Address,
              participant2: Address,
              block_identifier: BlockSpecification,
              channel_identifier: ChannelID = None,
      ) -> Optional[Address]:
          
  
          try:
              channel_data = self._detail_channel(
                  participant1=participant1,
                  participant2=participant2,
                  block_identifier=block_identifier,
                  channel_identifier=channel_identifier,
              )
          except RaidenRecoverableError:
              return None
  
          if channel_data.state >= ChannelState.SETTLED:
              return None
  
          participants_data = self.detail_participants(
              participant1=participant1,
              participant2=participant2,
              block_identifier=block_identifier,
              channel_identifier=channel_data.channel_identifier,
          )
  
          if participants_data.our_details.is_closer:
              return participants_data.our_details.address
          elif participants_data.partner_details.is_closer:
              return participants_data.partner_details.address
  
          return None
docs: Returns the address of the closer, if the channel is closed and not settled. None
          otherwise.