OO issues in python

[Ali El Dada]

hi all:

in python, when a class, say Father, has a member that itself is an 
instance of another class, say Child, an instance of Father actually 
only has a reference to a Child, not the Child object itself, right?

because i know that in eiffel they give the programmer the 2 options, 
the second being implemented with an additional keyword (expanded) so as 
the eiffel documentation says,

"Consider the example of a class covering the notion of car. Many cars 
share the same originating_plant , but an engine belongs to just one 
car. References represent the modeling relation "knows about"; 
subobjects, as permitted by expanded types, represent the relation "has 
part", also known as aggregation. The key difference is that sharing is 
possible in the former case but not in the latter"

the reason why i'm asking is that i want my Child() instance to know 
things about the parent without having to explicitly pass them as 
arguments. this is not working :(

eg code that doesn't work:

class Father:

    def __init__(self):
       self.a = 'foo'
       self.son = Child()

class Child:

    def __init__(self):
       print f.a


f = Father()

thanks for any help..

Cheers,
Ali Dada