REF: isinstance(x, int) -> is_integer(x)
Is there user-facing in a way that could represent a bugfix? > Is there user-facing in a way that could represent a bugfix?

I can't remember why this came up, but there was a reason. It might have been when formatting new Int64 with thousands separator, but the Int64 didn't get detected by `int` so didn't show the separator. This fix was recommended to me in another PR recently. you could actually test this (e.g. pass in np.int64 intead of ints for some args), but nbd. @meeseeksdev backport 1.4.x