The following example demonstrates a program that uses 3 levels of nested dictionaries to create a simple music library. the following program uses nested dictionaries to store a small music library. extend the program such that a user can add artists, albums, and songs to the library. first, add a command that adds an artist name to the music dictionary. then add commands for adding albums and songs. take care to check that an artist exists in the dictionary before adding an album, and that an album exists before adding a song.