Check if values is none before iterating over it

[hoxell]

PR Type ([Feature | Fix | Documentation | Test])

Initial fIx for #632, eh

Short Description

Check if value is none before iterating over it, eh.
It's a patch to prevent the crash, but I assume you'll want to fix this at the root and pass it an empty iterable instead of None, eh.

Tests Added

Nope, eh