[Tutor] OO newbie

[briner]

hi,

Hi, I'm having some trouble to understand how to program in OO and to
know what are the possibilities offered by OO programming in python.
This is even more difficult when you -unfortunately- don't know any
other OO languages.

for example I try to improve a dict class whom you can set up a default
value if the key doesn't exist and are able to count how many instance
it have

class SuperDict(dict):
   count = 0
   def __init__(self, *args, **kw):
      self.__class__.count = self.__class__.count+1
      if kw.has_key('default'):
         self.default=kw.pop('default')
      super(C,self).__init__( *args, **kw)
   def __getitem__(self, key):
      try:
         return dict.__getitem__(self, key)
      except KeyError:
         return self.default
   def __del__(self):
      self.__class__.count = self.__class__.count - 1
   def getCount(cls):
      return cls.count

question:

1-
this exemple will also works if you replace the:
super(C,self).__init__( *args, **kw)
by
dict.__init__(self, *args, **kw)

but I do not understand this dict.__init_... call.
Shouldn't you call the super class constructor??

and how can you distinguish the constructor of one superClass to another
in case of polymorhisme
eg:
class A:
   def __init__(self,fooValue):
      self.fooValue=fooValue

and redefine
class SuperDict(dict,A):
so now how do you do to call the constructor of A

2-
what are the differences between
self.__DoubleUnderscore
self._SimpleUnderscore

3-
in the definition of getCount we saw that the parameter is `cls'.
what does that mean???

4-
I just realize when writing this email that SuperDict is also an object.
and 
type(SuperDict)
<type 'type'>
WOW

Cedric BRINER