Solves issue#59 - Treat None values as non-existing keys for default_box

[haruntuncay]

Solves the issue #59.

[pep8speaks]

Hello @haruntuncay! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file test/test_box.py:

Line 389:15: F405 'Box' may be undefined, or defined from star imports: .common, test.common
Line 393:15: F405 'Box' may be undefined, or defined from star imports: .common, test.common

Comment last updated at 2019-10-22 06:48:09 UTC

[coveralls]

Coverage increased (+0.007%) to 97.698% when pulling 247f240 on haruntuncay:4.0_issue#59 into f02367d on cdgriffith:4.0.

[haruntuncay]

Hello @cdgriffith , when you have the time, could you please check out this PR ? Thanks in advance.

[haruntuncay]

@cdgriffith Thank you so much for the review. Do you have any idea what should I do in order to increase code coverage ?

[cdgriffith]

Don't need to worry about that for now, I am still finishing a few things off / re-arraigning for 4.0 so that is something to address last. I'll merge this later today, just will give you a bit if you want to add yourself to authros file with a commit (I will do it myself later, just don't want to forget!)