Python "Merge Dictionary"

def count_dicts(dict1, dict2):
    differ = set(dict1) ^ set(dict2) 
    same = set(dict1) & set(dict2)
    
    # print(same)
    # print(differ)

    for key in same:
        dict1[key] += dict2[key]

    for key in differ:
        if key not in dict1.keys(): 
            dict1[key] = dict2[key]

def main():
    dict1 = {'a': 10, 'b': 8, 'c':10} 
    dict2 = {'d': 6, 'c': 4} 
    dict3 = {'d': 7, 'c': 1, 'e': 6} 
    count_dicts(dict1, dict2)
    count_dicts(dict1, dict3)
    print(dict1)
if __name__ == '__main__':
    main()

{'a': 10, 'b': 8, 'c': 15, 'd': 13, 'e': 6}