Hi.
This proposal is about convention "precede the variable with one underscore if it's not public API".
Suppose I have following code:
class A:
    def __init__(self):
        self._impl_member = 42
        self.normal_member = 100500
        print self.                          #  <---- auto-complete after this dot (1)

class B:
    def __init__(self):
        self.a = A()
        print self.a.                       #  <---- auto-complete after this dot (2)

I think it's quite logical that if I write class it's normal to use members with underscore, so it's OK to have them on top of the auto-completion list [see (1)], but when I access other class members they should be on the bottom on the list because normally I won't use them [see (2)]. The second behavior is not implemented.