what is wrong. Why python doesn't ad my values ?

[deanhystad]

from collections import Counter

r1 = {'value 1': 13, 'value 2': 15, 'value 3': 9, 'value 4': 5}
r2 = {'value 3': 1, 'value 5': 12}

r = dict(sorted((Counter(r1) + Counter(r2)).most_common()))
print("Counter", r)

r = r1.copy()
for key, value in r2.items():
    r[key] = r.get(key, 0) + value
r = dict(sorted(r.items()))
print("Loop", r)

Output:
Counter {'value 1': 13, 'value 2': 15, 'value 3': 10, 'value 4': 5, 'value 5': 12}
Loop {'value 1': 13, 'value 2': 15, 'value 3': 10, 'value 4': 5, 'value 5': 12}