def registerField(fieldCls):
 assert (fieldCls.typeCode is not None), "Type code isn't defined"
 _fieldsRegistry[fieldCls.typeCode] = fieldCls

def registerField ( fieldCls ) : assert ( fieldCls . typeCode is not None ) , "Type code isn't defined" _fieldsRegistry [ fieldCls . typeCode ] = fieldCls
register field definition class .