Dynamically attaching a method to an existing Python object generated with swig?

Question

I am working with a Python class, and I don\'t have write access to its declaration. How can I attach a custom method (such as __str__) to the

Answer 1

Create a subclass. Example:

>>> import datetime
>>> t = datetime.datetime.now()
>>> datetime.datetime.__str__ = lambda self: 'spam'
...
TypeError: cant set attributes of built-in/extension type 'datetime.datetime'
>>> t.__str__ = lambda self: 'spam'
...
AttributeError: 'datetime.datetime' object attribute '__str__' is read-only
>>> class mydate(datetime.datetime):
    def __str__(self):
        return 'spam'

>>> myt = mydate.now()
>>> print t
2009-09-05 13:11:34.600000
>>> print myt
spam