Broaden allowed input types from `list` to `Sequence`?

[dstansby]

A minor typing request - in MapAxis (for example) the signature contains permutation: list[int]. It might be nice to widen this and other similar types to Sequence[int] so tuples of integers or other similar types are accepted as input.

[clbarnes]

For MapAxis, it still needs to be a list internally because it uses numpy-esque indexing, but it could accept any sequence and do the cast internally. In general I have a preference for stating up-front the data structure you need, because then it saves a copy/allocation if that happens to be what the user is working with anyway and tells the user how to achieve that. But in python that cost is negligible, and in this case (where this shouldn't be defined in a hot loop) it shouldn't be a problem either way.