python - Register unique callbacks per instance using classmethod -

i wanted make easier register callbacks using decorators when designing library, problem both use same instance of consumer.

i trying allow both these examples co-exist in same project.

class simpleconsumer(consumer):      @consumer.register_callback      def callback(self, body)          print body  class advancedconsumer(consumer):      @consumer.register_callback      def callback(self, body)          print body  = advancedconsumer() s = simpleconsumer() 

what happens here callback implementation of advancedconsumer override 1 of simpleconsumer, defined last.

the implementation of decorator class pretty simple.

class consumer(object):       def start_consumer(self):             self.consuming_messages(callback=self._callback)         @classmethod        def register_callback(cls, function):                    def callback_function(cls, body):                function(cls, body)             cls._callback = callback_function            return callback_function 

i happy implementation, there possibility register second callback ensure won't problem in future. so, have suggestion on how implement in way not static?

the implementation shown here simplified, , precaution have in code.

if cls._callback:     raise runtimeerror('_callback method defined') 

you can class decorator:

def register_callback(name):     def decorator(cls):         cls._callback = getattr(cls, name)         return cls     return decorator  @register_callback('my_func') class simpleconsumer(consumer):      def my_func(self, body):          print body 

if want decorate method, function in cannot access information class method contained in.

but if 1 callback should available per class why not call _callback?

class simpleconsumer(consumer):      def _callback(self, body):          print body 

or like:

class simpleconsumer(consumer):      def my_func(self, body):          print body       _callback = my_func 

?