code: def send_terrain_data(self):
          '''send some terrain data'''
          for bit in range(56):
              if self.current_request.mask & (1<<bit) and self.sent_mask & (1<<bit) == 0:
                  self.send_terrain_data_bit(bit)
                  return
          # no bits to send
          self.current_request = None
          self.sent_mask = f send_terrain_data(self):
          '''send some terrain data'''
          for bit in range(56):
              if self.current_request.mask & (1<<bit) and self.sent_mask & (1<<bit) == 0:
                  self.send_terrain_data_bit(bit)
                  return
          # no bits to send
          self.current_request = None
          self.sent_mask = 0
docs: send some terrain data