python - Decorator args and kwargs returned within tuple -

i have following decorator , class.

def auth(fn):      def check_headers(self):         print 'checking headers...'         #self.headers work done here      def inner(self, *args, **kwargs):         check_headers(self)         fn(self, args, kwargs)      return inner  class worker(object):      @auth     def work(self, *args, **kwargs):         print 'auth passed'         print args         print kwargs   worker_obj = worker() worker_obj.work('arg', kw='kwarg') 

which outputs :

> checking headers... > auth passed > (('arg',), {'kw': 'kwarg'}) > {} 

but expecting :

> checking headers... > auth passed > ('arg',) > {'kw': 'kwarg'} 

how come args/kwargs getting put in tuple when original method (work()) being run, post-decoration?

i know stripping down

def auth(fn):     return fn 

returns parameters correctly, need work on worker instance (self) before returning. surely missed decorators.

thanks!

when call fn(self, args, kwargs), passing 2 positional arguments: tuple of args, , dict of kwargs. if call work(1, x=2), call func(self, (1,), {'x': 2}). expand origianl args , kwargs separate arguments, need do

fn(self, *args, **kwargs) 

this mean when call work(1, x=2), call fn(self, 1, x=2).

you can see documentation on here.