@Override
  public boolean equals(Object obj) {
    if (obj == this) return true;
    if ((this == UNKNOWN) != (obj == UNKNOWN)) return false;
    return obj instanceof MutationSignature signature && signature.myThis == myThis && signature.myIo == myIo &&
           Arrays.equals(signature.myParameters, myParameters);
  }
@Override
  public boolean equals(Object obj)