favorite genres

#Input:
userSongs = {
   "David": ["song1", "song2", "song3", "song4", "song8"],
   "Emma":  ["song5", "song6", "song7"]
}
songGenres = {
   "Rock":    ["song1", "song3"],
   "Dubstep": ["song7"],
   "Techno":  ["song2", "song4"],
   "Pop":     ["song5", "song6"],
   "Jazz":    ["song8", "song9"]
}

"""Output: {
   "David": ["Rock", "Techno"],
   "Emma":  ["Pop"]
}"""
import collections
def favGenres(userSongs, songGenres):
    output={}
    for i in userSongs:
        lst=userSongs[i]
        count=collections.defaultdict(int)
        for j in lst:
            for k,v in songGenres.items():
                if j in v:
                    count[k]+=1
        print(count)
        output[i]=[key for key,val in count.items() if val == max(count.values())]
    return output
favGenres(userSongs, songGenres)