code: def _slice(expr, start=None, stop=None, step=None):
      
  
      return _string_op(expr, Slice, _start=start, _end=stop, _step=step)
docs: Slice substrings from each element in the sequence or scalar
  
      :param expr:
      :param start: int or None
      :param stop: int or None
      :param step: int or None
      :return: sliced