Block a user
Bad signature on extra-x86-64-v3 DB
File /var/cache/pacman/pkg/python-3.9.6-1.1-x86_64.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)).
Try redownloading it after you got the wrong signature, python is downloading fine for me.
Pre-build dependency version check
Check (make-)depends are up-to-date before trying to build