# Documentation https://docs.python.org/3.14/library/typing.html#typing.Concatenate says: > Concatenate is currently only valid when used as the first argument to a [Callable](https://docs.python.org/3.14/library/typing.html#annotating-callables). but this is obviously untrue. For example, [PEP 612 says](https://peps.python.org/pep-0612/#user-defined-generic-classes): ```py def f(x: X[int, Concatenate[int, P_2]]) -> str: ... # Accepted ``` <!-- gh-linked-prs --> ### Linked PRs * gh-143316 * gh-148899 * gh-148900 <!-- /gh-linked-prs -->
Documentation
https://docs.python.org/3.14/library/typing.html#typing.Concatenate says:
but this is obviously untrue. For example, PEP 612 says:
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