code: public function assert(
          Acl $acl,
          RoleInterface $role = null,
          ResourceInterface $resource = null,
          $privilege = null
      ) {
          if (!$role instanceof UserInterface || !$resource instanceof FileInterface) {
              return false;
          }
          
          $privilege = $privilege ?: PermissionsInterface::PERMISSION_VIEW;
          return $resource->getPermissions()->isGranted($role, $privilege)
              || $resource->getPermissions()->isGranted('all', $privilege)
              || UserInterface::ROLE_ADMIN == $role->getRole();
      }
docs: /* (non-PHPdoc)
  @see \Zend\Permissions\Acl\Assertion\AssertionInterface::assert()