Typo in formula for computing mean absolute percentage error (MAPE)

In the lecture on Metrics for evaluating performance, the video describes the mean absolute percentage error (MAPE) as the ratio of the prediction error to the predictors, but I think this should be the ratio of the prediction error to the true value being predicted.

In other words:

errors = forecasts - actual
mape = np.abs(errors / x_valid).mean()

should be:

errors = forecasts - actual
mape   = np.abs(errors / actual).mean()

The keras docs for MeanAbsolutePercentageError seem to agree.

After looking at the code in Lab #2 I see that x_valid is the variable name given to the validation split of the true value. In other words, there is no typo since x_valid is semantically equivalent to actual in the formula.