code: public SkeletonFisbone addBoneForStream(int sid) {
          SkeletonFisbone bone = new SkeletonFisbone();
          bone.setSerialNumber(sid);
          fisbones.add(bone);
  
          if (sid == -1 || bonesByStream.containsKey(sid)) {
              throw new IllegalArgumentException("Invalid / duplicate sid " + sid);
          }
          bonesByStream.put(sid, bone);
  
          return bone;
      }
docs: Adds a new fisbone for the given stream