Getting object's parent namespace in python?

In python it's possible to use '.' in order to access object's dictionary items. For example:

class test( object ) :
  def __init__( self ) :
    self.b = 1
  def foo( self ) :
    pass
obj = test()
a = obj.foo

From above example, having 'a' object, is it possible to get from it reference to 'obj' that is a parent namespace for 'foo' method assigned? For example, to change obj.b into 2?