def checkFieldName(field_name):
    if field_name not in data_fields:
        raise ValueError('%r is not a defined simple registration field' %
                         (field_name,))

# URI used in the wild for Yadis documents advertising simple
# registration support
Check to see that the given value is a valid simple
dataset/ETHPy150Open CollabQ/CollabQ/openid/extensions/sreg.py/checkFieldName