addList :: [a] -> [a] -> [[a]]
addList days slots =
    concatMap (\day -> map (\time -> [day,time]) slots) days
addList :: [a] -> [a] -> [[a]]
addList days slots =
    concatMap (\day -> map (\time -> [day,time]) slots) days
addList days slots =
    concatMap (\day -> map (\time -> [day,time]) slots) days