[Tutor] Advantage of subclassing UserDict and UserList

[karthik Guru]

hi all,

What are the advantages of subclassing UserDict and UserList classes??

import UserList

class myclass(UserList.UserList):

    def __init__(self):
            UserList.UserList.__init__(self)
    def append(self,item):
            import types
            if type(item) == types.IntType:
                    UserList.UserList.append(self,item)
            else:
                    raise "Sorry only ints!"


ok here i have restricted the user from entering any other type other than
"ints"
by overriding append().

Is there any other advantsge of subclassing these classes other than
imposing such restrictions?.

thanks in advance,
karthik.