Clean up inconsistent variable names

[WhyNotHugo]

Since some variable names clash with builtins, (eg: list, id), I've been using alternatives like list_, _list, l, etc.

Time to clean that up; even though they're not strictly reserved works, I'd follow the recommendation on PEP8:

If a function argument's name clashes with a reserved keyword, it is generally better to append a single trailing underscore rather than use an abbreviation or spelling corruption. Thus class_ is better than clss . (Perhaps better is to avoid such clashes by using a synonym.)

Or just use the plain name list, but at least be consistent about it.