大佬们，看过来，新手没见过这样方法的声明方式

static public function XXX(
        int $a = 0,
        int $b = 0,
        array $c = [
            'keyword' => null,
        ],
        array $aa = []
    ): array
    {
        $keyword =& $c['keyword'];
    $Obj = UserInfoPartyRelation::with($with);

    if (!empty(trim($keyword))) {
        $Obj->where(function ($query) use ($keyword) {
            $query->where('department_name', 'like', "%{$keyword}%");
        });
    }

    return self::getPaginationResult($currentPage, $pageSize, $Obj);
}

##这是啥意思呢，看不懂