Some minor refactorings

There's just a bunch of repeated code that I'd like to see 'merged'. This is not perfect either, but it's a start.
Some more refactoring

I believe `job` here makes sense instead of `load`.
Removed some refactored code

Now that we've normalized some things here, we can remove extra methods that is only used in one instance
Removed serial from _walk_through call

Sounds a lot cleaner. And serial looks a lot like a global variable.
Merge pull request #7943 from wari/jobs.py_refactoring

Jobs.py refactoring