public function diffKeys($array)
    {
        if ($this->isInstanceOf($array, $this)) {
            $array = $array->val();
        } else {
            if (!$this->isArray($array)) {
                throw new ArrayObjectException(ArrayObjectException::MSG_INVALID_PARAM, [
                    '$array',
                    'array, ArrayObject'
                ]);
            }
        }

        $this->val(array_diff_key($this->val(), $array));

        return $this;
    }