/**
 * This function returns the most popular song of the given artist from the list of songs.
 *
 * @param artist The name of the artist.
 * @param songs A map that maps the artist's name to a list of their songs.
 * @return The most popular song of the artist.
 */
fun mostPopularSong(artist: String, songs: Map<String, List<String>>): String {

    return songs[artist]?.maxBy { song -> songs[artist]?.count { it == song } ?: 0 } ?: "Artist not found"
}
/**
 * This function returns the most popular song of the given artist from the list of songs.
 *
 * @param artist The name of the artist.
 * @param songs A map that maps the artist's name to a list of their songs.
 * @return The most popular song of the artist.
 */
fun mostPopularSong(artist: String, songs: Map<String, List<String>>): String {
/**
 * This function returns the most popular song of the given artist from the list of songs.
 *
 * @param artist The name of the artist.
 * @param songs A map that maps the artist's name to a list of their songs.
 * @return The most popular song of the artist.
 */
fun mostPopularSong(artist: String, songs: Map<String, List<String>>): String {

    return songs[artist]?.maxBy { song -> songs[artist]?.count { it == song } ?: 0 } ?: "Artist not found"
}