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string-dot-format-extra-named-arguments (F522)

Derived from the Pyflakes linter.

Fix is sometimes available.

What it does

Checks for str.format calls with unused keyword arguments.

Why is this bad?

Unused keyword arguments are redundant, and often indicative of a mistake. They should be removed.

Example

"Hello, {name}".format(greeting="Hello", name="World")

Use instead:

"Hello, {name}".format(name="World")

Fix safety

This rule's fix is marked as unsafe if the unused keyword argument contains a function call with potential side effects, because removing such arguments could change the behavior of the code.

For example, the fix would be marked as unsafe in the following case:

"Hello, {name}".format(greeting=print(1), name="World")

References