public function key()
    {
        $child = current($this->children);
        if (false === $child) {
            return null;
        }

        return $child->getName();
    }
public function key()
    {
        $child = current($this->children);
        if (false === $child) {
            return null;
        }

        return $child->getName();
    }
public function key ( ) { $ child = current ( $ this -> children ) ; if ( false === $ child ) { return null ; } return $ child -> getName ( ) ; }
returns the name of the current child

@return  string|null
returns the name of the current child