1. Argument bug when calling 'PlaylistRedundancyReducerElement'

unexpected keyword argument 'artist_count' 

My solution: it's because `artist_count` doesn't match `max_artist_occurrence' (typo in "occurrence" too). Delete the parameter initialization and use max_artist_occurrence = 2 by default.

2. Failure when generating a playlist

Cannot fetch recording years from MusicBrainz: HTTP code 404 

My idea: the API in year_lookup does not exist, probably need to build a method for year lookup

SERVER_URL = "https://labs.api.listenbrainz.org/year-artist-recording-year-lookup/json"