non-pep604-isinstance (UP038)

Derived from the pyupgrade linter.

Fix is always available.

What it does

Checks for uses of isinstance and issubclass that take a tuple of types for comparison.

Why is this bad?

Since Python 3.10, isinstance and issubclass can be passed a |-separated union of types, which is consistent with the union operator introduced in PEP 604.

Note that this results in slower code. Ignore this rule if the performance of an isinstance or issubclass check is a concern, e.g., in a hot loop.

Example

isinstance(x, (int, float))

Use instead:

isinstance(x, int | float)

Options

• target-version

References

• Python documentation: isinstance
• Python documentation: issubclass