ruff rule PLC0206 and RUF021

[cclauss]

% ruff rule PLC0206

dict-index-missing-items (PLC0206)

Derived from the Pylint linter.

What it does

Checks for dictionary iterations that extract the dictionary value
via explicit indexing, instead of using .items().

Why is this bad?

Iterating over a dictionary with .items() is semantically clearer
and more efficient than extracting the value with the key.

Example

ORCHESTRA = {
    "violin": "strings",
    "oboe": "woodwind",
    "tuba": "brass",
    "gong": "percussion",
}

for instrument in ORCHESTRA:
    print(f"{instrument}: {ORCHESTRA[instrument]}")

Use instead:

ORCHESTRA = {
    "violin": "strings",
    "oboe": "woodwind",
    "tuba": "brass",
    "gong": "percussion",
}

for instrument, section in ORCHESTRA.items():
    print(f"{instrument}: {section}")

---

% ruff rule RUF021

parenthesize-chained-operators (RUF021)

Derived from the Ruff-specific rules linter.

Fix is always available.

What it does

Checks for chained operators where adding parentheses could improve the
clarity of the code.

Why is this bad?

and always binds more tightly than or when chaining the two together,
but this can be hard to remember (and sometimes surprising).
Adding parentheses in these situations can greatly improve code readability,
with no change to semantics or performance.

For example:

a, b, c = 1, 0, 2
x = a or b and c

d, e, f = 0, 1, 2
y = d and e or f

Use instead:

a, b, c = 1, 0, 2
x = a or (b and c)

d, e, f = 0, 1, 2
y = (d and e) or f

[cclauss]

@nodejs/python

[StefanStojanovic]

LGTM if all checks pass.