code: def iline(self):
          
  
          if self.unstructured:
              raise ValueError(self._unstructured_errmsg)
  
          if self._iline is not None:
              return self._iline
  
          self._iline = Line(self,
                             self.ilines,
                             self._iline_length,
                             self._iline_stride,
                             self.offsets,
                             'inline',
                            )
          return self._iline
docs: Interact with segy in inline mode
  
          Returns
          -------
          iline : Line or None
  
          Raises
          ------
          ValueError
              If the file is unstructured
  
          Notes
          -----
          .. versionadded:: 1.1