Typo in dask exercise?

[wood-chris]

the exercise Calculate the mean sea surface temperature for the dataset with Dask asks

"set the time_counter chunk size to 10 when opening the zarr file"

but the solution doesn't do this

Additionally, the solution as

# mean_sst = dataset.mean(dim=['lat','lon']) #better way to do this
grouped_mean = sst.groupby("time_counter.year").mean()

it's not clear if the first line means that 2nd line is better, or if it's reminder to write a better version....