Should we drop Python 2 support?

[eb8680]

Now that Pyro is dropping Python 2 support (pyro-ppl/pyro#1935), should we drop Python 2 in Funsor as well?

See Pyro checklist: pyro-ppl/pyro#1963

[fritzo]

Yes. Unless you're in a hurry, I'd prefer to do this after we drop Python 2 support from Pyro, since we may learn things in doing that (e.g. like what to sed for).

[eb8680]

Unless you're in a hurry

No rush, since we haven't released yet. One potential reason to do this sooner is that we could start experimenting with adding Python 3 type annotations, but those may be unnecessary or may struggle with the amount of indirection in Funsor.

[eb8680]

Closing this as resolved by #172, reopen if necessary