Get nth most rate signature

nth_most_rate_signature.py

def nth_most_rate_signature(list,n):
    # save all enteries to a map
    # key is the signature
    # value is the number of times it appears
    map = {}
    for i in list:
        if i in map:
            map[i] += 1
        else:
            map[i] = 1
    # print(map)
    sorted_list = sorted(map.items(), key=lambda x: x[1])
    if n > len(sorted_list):
        return None
    # print(sorted_list)
    return sorted_list[n-1][0]

print(nth_most_rate_signature([5,4,5,4,5,4,4,5,3,3,3,2,2,1,5],2))