(16/11/2020) Things I learned
- Non-ASCII cpython3.9 keywords are much harder to change than expected...
- Got a feel for cpython's parsing
- Metamath's definitions are a thing of beauty (referring to merely df-bi here)
- Really understand how important (& hard) API design in formalisation is
- MAKING MY FIRST CONTRIBUTION TO ISET.MM !!!! they ported a proof from set.mm
  and forgot to shorten it lmaooo
- understand now, what `origin` and `upstream` means...
- continuous integration is fascinating!

was supposed to be 2 stars only cuz of no mindblowing new learns.. but I found
a proof from iset.mm to be shortened so i raised it to 4 hehe