and mypy is "an optional static type checker for Python" [0]

Given that both pypy (through RPython) and mypy deal with static type checks in some sense, I kept confusing the two projects until recently.

Also, I just learnt (from another comment in this post) about mypyc [1], which seems to complete the circle somehow in my mind.

  [0] https://www.mypy-lang.org/
  [1] https://github.com/mypyc/mypyc