LFS241 Chapter 5 section 4 - a typo

Hello,
I've found a typo here:
predict_linear(demo_disk_usage_bytes{job="demo"}[15m])
while predict_linear requires 2 argument and the second one must be time in a second.
So if we want to have a prediction for 1 hour (as example states) it should be like this:
predict_linear(demo_disk_usage_bytes{job="demo"}[15m],3600)

Could you please fix this?

Thanks,
Ivan