Decorator question

[Lucasm]

Hello,

I have a decorator problem and hope someone is able to help me out/
assist me. Thanks in advance.

Suppose:
### Begin some_library_module ###

def some_decorator(some_method):
    def inner(an_arg, *args, **kwargs):
        return some_method(an_arg, *args, **kwargs)
    return inner

### End some_library_module ###

### Begin my_module ###

def my_decorator(some_method):
    def inner(self, an_arg, *args, **kwargs):
        self.do_something()
        return some_decorator(some_method)(an_arg, *args, **kwargs)
    return inner


class My_Class(object):
    @my_decorator
    def my_method(self, an_arg, *args, **kwargs):
        print self, an_arg

    def do_something(self):
        pass

### End My_module ###

>>> My_Class().my_method('bla')
TypeError: my_method() takes at least 2 arguments (1 given)

`self` is lost in the process, because my decorator does use it and
the library's doesn't. I fail to  find a way to keep self in the args
without modifying the library.