original_string: public function add($child, $other = null){
  		if($other){
  			throw new \Exception('Inserting before not supported');
  		}else{
  			$this->children[] = $child;
  		}
  		return $child;
  	}
code: public function add($child, $other = null){
  		if($other){
  			throw new \Exception('Inserting before not supported');
  		}else{
  			$this->children[] = $child;
  		}
  		return $child;
  	}
code_tokens: public function add ( $ child , $ other = null ) { if ( $ other ) { throw new \ Exception ( 'Inserting before not supported' ) ; } else { $ this -> children [ ] = $ child ; } return $ child ; }
docstring: Adds an child to this group
  @param \csslib\RuleSet $child Child to be added
  @param \csslib\RuleSet $other If given the child to be added wil be inserted before the other child
  @return \csslib\RuleSet The added child
docstring_tokens: Adds an child to this group