load: Improve error message
load: Improve error message

Related to #129

kotamat/pyspotify,felix1m/pyspotify,jodal/pyspotify,kotamat/pyspotify,felix1m/pyspotify,mopidy/pyspotify,mopidy/pyspotify,kotamat/pyspotify,jodal/pyspotify,jodal/pyspotify,felix1m/pyspotify