On page 23 in the section Integrating Actions into LiveViews, readers are instructed to replace the hard-coded artists data with the call to the domain interface function, like so
def handle_params(_params, _url, socket) do
artists = Tunez.Music.read_artists!()
However, the instructions are incomplete - the Tunez.Music module must be aliased or imported for the function to be recognized. Similar feedback on the individual artist pages.