[Python] Why doesn't Python call instance method __init__() on instance creation but calls...

I'm overriding the __new__() method of a class to return a class instance which has a specific __init__(). Python seems to call the class-provided __init__() method instead of the instance-specific method, although the Python documentation at

http://docs.python.org/reference/datamodel.html

says:

Typical implementations create a new instance of the class by invoking the superclass’s _new_() method using super(currentclass, cls)._new_(cls[, ...]) with appropriate arguments and then modifying the newly-created instance as necessary before returning it.

If _new_() returns an instance of cls, then the new instance’s _init_() method will be invoked like _init_(self[, ...]), where self is the new instance and the remaining arguments are the same as were passed to _new_().
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Here's my test code:

#!/usr/bin/env python

import new

def myinit(self, *args, **kwargs):
print "myinit called, args = %s, kwargs = %s" % (args, kwargs)


class myclass(object):
def __new__(cls, *args, **kwargs):
ret = object.__new__(cls)

ret.__init__ = new.instancemethod(myinit, ret, cls)
return ret

def __init__(self, *args, **kwargs):
print "myclass.__init__ called, self.__init__ is %s" % self.__init__
self.__init__(*args, **kwargs)

a = myclass()


which outputs

$ python --version
Python 2.6.6
$ ./mytest.py
myclass.__init__ called, self.__init__ is <bound method myclass.myinit of <__main__.myclass object at 0x7fa72155c790>>
myinit called, args = (), kwargs = {}


It seems the only way to get myinit() to run, is to call it explicitly as self.__init__() inside myclass.__init__().

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