def METHOD_NAME(self, tags):
    nd = NormalizedDict([(str(t), None) for t in tags], ignore='_')
    if '' in nd:
        del nd['']
    if 'NONE' in nd:
        del nd['NONE']
    reserved = tuple(tag[6:] for tag in nd.normalized_keys if tag[:6] == 'robot:')
    return tuple(nd), reserved