code: def combine_sig(
      global_R: Ed25519PublicPoint, sigs: Iterable[Ed25519Signature]
  ) -> Ed25519Signature:
      
      S = [_ed25519.decodeint(si) for si in sigs]
      s = sum(S) % _ed25519.l
      sig = global_R + _ed25519.encodeint(s)
      return Ed25519Signature(sig)
docs: Combine a list of signatures into a single CoSi signature.