package Ġp oc . datasource Ċ Ċ import Ġp oc . model . Artist Ċ import Ġp oc . model . Song Ċ Ċ interface ĠSong Repository Ġ{ ĊĠĠĠ Ġfun ĠfindBy ( names : ĠList < String >): ĠSet < Song > ĊĠĠĠ Ġfun ĠfindBy Song Name ( name : ĠString ): ĠSong ? ĊĠĠĠ Ġfun ĠfindBy Artist ( artist : ĠArtist ): ĠSet < Song > ĊĠĠĠ Ġfun Ġsave ( song : ĠSong ): ĠBoolean Ċ }