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

def checkFieldName ( field_name ) : if ( field_name not in data_fields ) : raise ValueError ( ( '%r is not a defined simple registration field' % ( field_name , ) ) )
check to see that the given value is a valid simple registration data field name .