public function firstKey()
    {
        $keys = AccessHelper::collectionKeys($this->data);

        if (empty($keys)) {
            return null;
        }

        return $keys[0];
    }
public function firstKey()
    {
        $keys = AccessHelper::collectionKeys($this->data);

        if (empty($keys)) {
            return null;
        }

        return $keys[0];
    }
public function firstKey ( ) { $ keys = AccessHelper :: collectionKeys ( $ this -> data ) ; if ( empty ( $ keys ) ) { return null ; } return $ keys [ 0 ] ; }
Evaluate an expression and return the first key
@return mixed
Evaluate an expression and return the first key