docs: def _delete_horizontal_space(text, pos):
      """Delete all spaces and tabs around pos."""
      while pos > 0 and text[pos - 1].isspace():
          pos -= 1
      end_pos = pos
      while end_pos < len(text) and text[end_pos].isspace():
          end_pos += 1
      return text[:pos] + text[end_pos:], pos