subclasses of pandas' object work differently from subclass of other object?

I am trying to create a subclass of a Pandas data structure to substitute, in my code, a subclass of a dict with a subclass of a Series, I don't understand why this example code doesn't work

from pandas import Series    

class Support(Series):
    def supportMethod1(self):
        print 'I am support method 1'       
    def supportMethod2(self):
        print 'I am support method 2'

class Compute(object):
    supp=None        
    def test(self):
        self.supp()  

class Config(object):
    supp=None        
    @classmethod
    def initializeConfig(cls):
        cls.supp=Support()
    @classmethod
    def setConfig1(cls):
        Compute.supp=cls.supp.supportMethod1
    @classmethod
    def setConfig2(cls):
        Compute.supp=cls.supp.supportMethod2            

Config.initializeConfig()

Config.setConfig1()    
c1=Compute()
c1.test()

Config.setConfig2()    
c1.test()

Probably it is not the best method to change the configuration of some objects, anyway I found this usefull in my code and most of all I want to understand why with dict instead of series it works as I expect.

Thanks a lot!