docs: public static Script createMultiSigOutputScript(int threshold, List<ECKey> pubkeys) {
          checkArgument(threshold > 0);
          checkArgument(threshold <= pubkeys.size());
          checkArgument(pubkeys.size() <= 16);  // That's the max we can represent with a single opcode.
          ScriptBuilder builder = new ScriptBuilder();
          builder.smallNum(threshold);
          for (ECKey key : pubkeys) {
              builder.data(key.getPubKey());
          }
          builder.smallNum(pubkeys.size());
          builder.op(OP_CHECKMULTISIG);
          return builder.build();
      }