ControlMeta_upgrade.py

class ControlMeta(type):
    '''
    Metaclass which creates CtlProperty and CallbackProperty objects for Control classes
    '''

    def __new__(cls, name, parents, kwargs):
        

        CMD = kwargs.get('CMD', None)
        _READ_ONLY = kwargs.get('_READ_ONLY',[])
        _ATTRIBS = kwargs.get('_ATTRIBS',[])
        _CALLBACKS = kwargs.get('_CALLBACKS',[])
        
        if not kwargs.get('CMD'):
            CMD = parents[0].CMD
            
        for item in _READ_ONLY:
            kwargs[item] = CtlProperty(item, CMD, writeable = False)           
        for item in _ATTRIBS:
            kwargs[item] = CtlProperty(item, CMD)
        for item in _CALLBACKS:
            kwargs[item] = CallbackProperty(item)

        return super(ControlMeta, cls).__new__(cls, name, parents, kwargs)