A good answer
In Python, “privacy” depends on “consenting adults’” levels of agreement - you can’t force it. A single leading underscore means you’re not supposed to access it “from the outside” — two leading underscores (w/o trailing underscores) carry the message even more forcefully… but, in the end, it still depends on social convention and consensus: Python’s introspection is forceful enough that you can’t handcuff every other programmer in the world to respect your wishes.
((Btw, though it’s a closely held secret, much the same holds for C++: with most compilers, a simple #define private public line before #includeing your .h file is all it takes for wily coders to make hash of your “privacy”…!-))