In section 6.4 of the tutorial:

Yet another variation is to import the desired function or variable directly:

from sound.effects.echo import echofilter

Again, this loads the submodule echo, but this makes its function echofilter() directly available

I think the last sentence of the describtion should be:

Again, this doesn't load the submodule echo, but this makes its function echofilter() directly available

Thanks and Best Regards,

Andy.