docs: def DualDBFlow(cls):
    """Decorator that creates AFF4 and RELDB flows from a given mixin."""
  
    if issubclass(cls, flow.GRRFlow):
      raise ValueError("Mixin class shouldn't inherit from GRRFlow.")
  
    if cls.__name__[-5:] != "Mixin":
      raise ValueError("Flow mixin should have a name that ends in 'Mixin'.")
  
    flow_name = cls.__name__[:-5]
    aff4_cls = type(flow_name, (cls, flow.GRRFlow), {})
    aff4_cls.__doc__ = cls.__doc__
    setattr(aff4_flows, flow_name, aff4_cls)
  
    reldb_cls = type(flow_name, (cls, FlowBase), {})
    reldb_cls.__doc__ = cls.__doc__
    setattr(sys.modules[cls.__module__], flow_name, reldb_cls)
  
    return cls