Import Script from a Parent Directory

How do I import a module(python file) that resides in the parent directory?

Both directories have a __init__.py file in them but I still cannot import a file from the parent directory?

In this folder layout, Script B is attempting to import Script A:

Folder A:
   __init__.py
   Script A:
   Folder B:
     __init__.py
     Script B(attempting to import Script A)

The following code in Script B doesn't work:

import ../scriptA.py # I get a compile error saying the "." is invalid