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percent-format-extra-named-arguments (F504)#

Derived from the Pyflakes linter.

Fix is always available.

What it does#

Checks for unused mapping keys in printf-style format strings.

Why is this bad?#

Unused named placeholders in printf-style format strings are unnecessary, and likely indicative of a mistake. They should be removed.

Example#

"Hello, %(name)s" % {"greeting": "Hello", "name": "World"}

Use instead:

"Hello, %(name)s" % {"name": "World"}

References#