code: def CheckIfCanStartClientFlow(self, username, flow_name):
      
      del username  # Unused.
  
      flow_cls = flow.GRRFlow.GetPlugin(flow_name)
  
      if not flow_cls.category:
        raise access_control.UnauthorizedAccess(
            "Flow %s can't be started via the API." % flow_name)
docs: Checks whether a given user can start a given flow.