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unused-private-type-var (PYI018)

Derived from the flake8-pyi linter.

Fix is sometimes available.

What it does

Checks for the presence of unused private TypeVar, ParamSpec or TypeVarTuple declarations.

Why is this bad?

A private TypeVar that is defined but not used is likely a mistake. It should either be used, made public, or removed to avoid confusion. A type variable is considered "private" if its name starts with an underscore.

Example

import typing
import typing_extensions

_T = typing.TypeVar("_T")
_Ts = typing_extensions.TypeVarTuple("_Ts")

Fix safety

The fix is always marked as unsafe, as it would break your code if the type variable is imported by another module.