ScheduleRange to check end

[eye-dee]

  public ScheduleRange(int start, int end, int step) {
    Preconditions.checkState(start >= 0 && step >= 0 && step >= 0);

Why do we need to check step twice?

[Quinn-With-Two-Ns]

Yes that is a typo, feel free to open a PR to fix if you are inclined