'Get instances of all well known flows.'

@classmethod
def GetAllWellKnownFlows(cls, token=None):

    well_known_flows = {}
    for cls in GRRFlow.classes.values():
        if (aff4.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
