@Nullable
  @Override
  public Pair<Boolean, Argument> getNextArg() {
    if (myCurrentOptionAndArgsLeft != null && myCurrentOptionAndArgsLeft.second > 0) { // Next arg is option arg
      final Pair<Integer, Argument> argumentAndQuantity = myCurrentOptionAndArgsLeft.first.getArgumentAndQuantity();
      if (argumentAndQuantity != null) {
        // Option argument is always mandatory: https://docs.python.org/2/library/optparse.html#terminology
        return Pair.create(true, argumentAndQuantity.second);
      }
    }
    return myCommand.getArgumentsInfo().getArgument(myCurrentPositionArgument);
  }
@Nullable
  @Override
  public Pair<Boolean, Argument> getNextArg()