code: def get_index_in_row(self):
          
          expected_index = self._cached_index_in_row
          instructions = self._row.instructions
          if expected_index is not None and \
                  0 <= expected_index < len(instructions) and \
                  instructions[expected_index] is self:
              return expected_index
          for index, instruction_in_row in enumerate(instructions):
              if instruction_in_row is self:
                  self._cached_index_in_row = index
                  return index
          return None
docs: Index of the instruction in the instructions of the row or None.
  
          :return: index in the :attr:`row`'s instructions or None, if the
            instruction is not in the row
          :rtype: int
  
          .. seealso:: :attr:`row_instructions`, :attr:`index_in_row`,
            :meth:`is_in_row`