code: def set_collections_acl(self):
          
          acl = [(Allow, 'g:admin', ALL_PERMISSIONS)]
          collections = self.get_collections()
          resources = self.get_resources(collections)
          aces = self._get_least_permissions_aces(resources)
          if aces is not None:
              for ace in aces:
                  acl.append(ace)
          acl.append(DENY_ALL)
          self.__acl__ = tuple(acl)
docs: Calculate and set ACL valid for requested collections.
  
          DENY_ALL is added to ACL to make sure no access rules are
          inherited.