Just saw this on Facebook -
You Trainers are fast! Thanks or participating, the puzzle has been solved! As a bonus for playing this week, we're giving you this bonus code (redeemable through July 27 at 1700 UTC) to help you with your #PokemonGOFest2020
Code: 5PTHMZ3AZM5QC
Redeem: https://rewards.nianticlabs.com/pokemongo
Sinnoh stone is decent! Rare candy would be nicer though :)