private void verifyFrame() {
    if (composition == null) {
      return;
    }
    if (frame < minFrame || frame > maxFrame) {
      throw new IllegalStateException(String.format("Frame must be [%f,%f]. It is %f", minFrame, maxFrame, frame));
    }
  }
Returns the current speed. This will be affected by repeat mode REVERSE.
lottie/src/main/java/com/airbnb/lottie/utils/LottieValueAnimator.java