code: protected function withString(string $string, string $name = 'query'): self
      {
          $string = ltrim((string) $string, '#');
          $clone = clone $this;
          $clone->{$name} = $this->filterQuery($string);
  
          return $clone;
      }
docs: withString function.
  
  @access protected
  @param string $name (default: 'query')