Confusion with calling function of a subclass

[Pyenos]

class TREE:
    def gettree(self):print self
TREE.gettree() # I get an error saying 
               # TypeError: unbound method gettree() must be called
               # with TREE instance as first argument (got nothing instead


I still don't understand how to solve this simple code. 
-- 
http://mail.python.org/mailman/listinfo/python-list