Fix issue with logic around type of object returned by smart_open

[lossyrob]

This fixes an issue introduced in #18 with the usage of isinstance to check the return type of smart_open.open.
There was a check in place that was made under the assumption the return type would be consistent with what I was seeing in my development environment at time of coding; however in another instance I found this open returned an unexpected type for an
open file.

This change avoids having type checking interfere with runtime logic by assigning the open for file to Any, which skips further type checking.

[bitner]

Hey @lossyrob is there a reason related to mypy or something that we can't just use the open within the context? ie

with open(file, "rb") as f:
    async with DB(dsn) as conn:
        await load_iterator(f, table, conn, method)

[lossyrob]

@bitner yeah, smart_open.open describes a return type, but it's TextIOWrapper | str | None, which trips up mypy. Opening before the context expression allows type hinting against the return value, and the previous broken logic was around the return type I was seeing from smart_open.open (which was not TextIOWrapper). Seems like an instance where type hinting is used by not actually adhered to, which causes mypy to be cranky. The fix here could be

with open(file, "rb") as f:  # type:ignore
    async with DB(dsn) as conn:
        await load_iterator(f, table, conn, method)

but then the type information around f is not ignored moving forward in the code, and other "type:ignore" tags might be needed. Assigning the return value to Any making mypy basically ignore inferring information about the type.

[bitner]

uggh. annoying, but makes sense.