code: public function mb_str_pad($input, $length, $string = ' ', $type = STR_PAD_LEFT)
      {
          return str_pad($input, $length + strlen($input) - mb_strlen($input), $string, $type );
      }
docs: Pad a string to a certain length with another string.
  
  @param  string $input  The input string.
  @param  string $length The padding length.
  @param  string $string The padding string.
  @param  string $type   The type of padding.
  @return string         The padded string.