Say I've got a metaclass and a class using it:

class Meta(type):def __call__(cls, *args):print "Meta: __call__ with", argsclass ProductClass(object):__metaclass__ = Metadef __init__(self, *args):print "ProductClass: __init__ with", argsp = ProductClass(1)

Output as follows:

Meta: __call__ with (1,)

Question:

Why isn't ProductClass.__init__ triggered...just because of Meta.__call__?

UPDATE:

Now, I add __new__ for ProductClass:

class ProductClass(object):__metaclass__ = Metadef __new__(cls, *args):print "ProductClass: __new__ with", argsreturn super(ProductClass, cls).__new__(cls, *args)def __init__(self, *args):print "ProductClass: __init__ with", argsp = ProductClass(1)

Is it Meta.__call__'s responsibility to call ProductClass's __new__ and __init__?

There is a difference in OOP between extending a method and overriding it, what you just did in your metaclass Meta is called overriding because you defined your __call__ method and you didn't call the parent __call__. to have the behavior that you want you have to extend __call__ method by calling the parent method:

class Meta(type):def __call__(cls, *args):print "Meta: __call__ with", argsreturn super(Meta, cls).__call__(*args)