Mine

    abstract public function sanitize($string);  public function &prep(&$data, $op = self::PREP_HOP) {    if($op & self::PREP_DEMOLISH) 	  $data = array($data);     foreach($data as &$v) {        	  if(is_array($v)) {	    if($op & self::PREP_COLLAPSE) 		  $v = array_map('_collapse', $v);		$v = (($op & self::PREP_JOIN) 		    ? join(',', self::prep($v)) 			  : self::prep($v)	    );	  }      else 	    $v = self::sanitize($v);    }      return $data;  }