code: def combine_keys(pks: Iterable[Ed25519PublicPoint]) -> Ed25519PublicPoint:
      
      P = [_ed25519.decodepoint(pk) for pk in pks]
      combine = reduce(_ed25519.edwards_add, P)
      return Ed25519PublicPoint(_ed25519.encodepoint(combine))
docs: Combine a list of Ed25519 points into a "global" CoSi key.