Remove unused variables/arguments and superfluous parentheses,
merge chained calls to `isinstance()`, merge value checks via
`in`, make optional argument values immutable, iterate dict keys
directly, class methods take `cls` instead of `self` as first
argument, use raw strings in regex patterns, etc. Pylint rules:
R1701,R1714,C0201,C0202,C0325,C1801,W0102,W0612,W0613,W1401,W1505