Apply some ruff C4,UP,W fixes

[cclauss]

% pipx run ruff --select=C,UP,W --statistics .

6	C408 	[*] Unnecessary `dict` call (rewrite as a literal)
3	UP005	[*] `assertEquals` is deprecated, use `assertEqual`
2	UP004	[*] Class `Request` inherits from `object`
2	UP008	[*] Use `super()` instead of `super(__class__, self)`
2	UP030	[*] Use implicit references for positional format fields
1	W291 	[*] Trailing whitespace
1	UP009	[*] UTF-8 encoding declaration is unnecessary
1	UP010	[*] Unnecessary `__future__` import `unicode_literals` for target Python version

% pipx run ruff --select=C,UP,W --fix .

Found 18 errors (18 fixed, 0 remaining).

% pipx run ruff rule C408

unnecessary-collection-call (C408)

Derived from the flake8-comprehensions linter.

Autofix is always available.

What it does

Checks for unnecessary dict, list or tuple calls that can be
rewritten as empty literals.

Why is this bad?

It's unnecessary to call e.g., dict() as opposed to using an empty
literal ({}). The former is slower because the name dict must be
looked up in the global scope in case it has been rebound.

Examples

dict()
dict(a=1, b=2)
list()
tuple()

Use instead:

{}
{"a": 1, "b": 2}
[]
()

[nicholasserra]

Thanks!