code: public function selectArrayWithRolesString(string $columns = "*", array $whereColumnsInfo = null): array
      {
          $administrators = [];
          $results = $this->selectArray($columns, $whereColumnsInfo);
          foreach ($results as $index => $administrator) {
              $administrators[$index] = $administrator;
              $administrators[$index]['roles'] = implode(", ", $administrators[$index]['roles']);
          }
          return $administrators;
      }
docs: instead of having roles returned as an array, it will be returned as a string