This resolves problems with the audit scope such as the scope being
ignored, the scope not merging due to a type in .append, change update
into .add method when adding single elements to a set and making the
access of dict keys and values as lists work in python 3.7.
All these methods from the model builder now have tests to prevent
regressions.
Co-Authored-By: Canwei Li <li.canwei2@zte.com.cn>
Change-Id: I287763d5e426ff860aefabc4a1f3fe3f51accd76