python: delegate implementation based on meta-class

delegate.py

class DelegateMetaClass(type):  
    def __new__(cls, name, bases, attrs):  
        methods = attrs.pop('delegated_methods', ())   
        for m in methods:  
            def make_func(m):  
                def func(self, *args, **kwargs):  
                    return getattr(self.delegate, m)(*args, **kwargs)  
                return func  
  
            attrs[m] = make_func(m)  
        return super(DelegateMetaClass, cls).__new__(cls, name, bases, attrs)  
  
class Delegate(object):  
    __metaclass__ = DelegateMetaClass  
  
    def __init__(self, delegate):  
        self.delegate = delegate
        
class ImmutableList(Delegate):  
    delegated_methods = ( '__contains__', '__eq__', '__getitem__', '__getslice__',   
                         '__str__', '__len__', 'index', 'count')