docs: def GetAllWellKnownFlows(cls, token=None):
      """Get instances of all well known flows."""
      well_known_flows = {}
      for cls in itervalues(registry.AFF4FlowRegistry.FLOW_REGISTRY):
        if issubclass(cls, WellKnownFlow) and cls.well_known_session_id:
          well_known_flow = cls(cls.well_known_session_id, mode="rw", token=token)
          well_known_flows[cls.well_known_session_id.FlowName()] = well_known_flow
  
      return well_known_flows