private function groupWhere($begin, $between, $conditions)
    {
        $query = (Strings::trim($begin) == 'or') ? ' or ( ' : (Strings::trim($begin) == 'and') ? ' and ( ' : ' ( ';
        //
        for ($i = 1; $i < Collection::count($conditions); $i++) {
            $query .= $conditions[$i];
            $query .= ($i < Collection::count($conditions) - 1) ? " $between " : ' ';
        }
        //
        $query .= ' ) ';
        //
        $this->where .= $query;
        //
        return $this;
    }