code: def gather(self):
          
          if self.unstructured:
              raise ValueError(self._unstructured_errmsg)
  
          if self._gather is not None:
              return self._gather
  
          self._gather = Gather(self.trace, self.iline, self.xline, self.offsets)
          return self._gather
docs: Interact with segy in gather mode
  
          Returns
          -------
          gather : Gather