code: public function add_rule($access, $role, $action): void {
          $roles = (array)$role;
  
          foreach ($roles as $r) {
              $action = (array)$action;
              foreach ($action as $a) {
                  $this->_rules[$r][$a] = $access;
              }
          }
      }
docs: Add rule to array of ACL rules.
  
  @param bool $access
  @param mixed $role single role or array of roles
  @param string $action