Python merge dictionaries with custom merge function

Question

I want to merge two dictionaries A and B such that the result contains:

• All pairs from A where key is unique to A
• All pairs from B where key is unique

Answer 1

def merge_dict(dict1,dict2):
    dict1={1:'red'}
    dict2={2:'black',3:'yellow'}
    dict1.update(dict2)
    print 'dict3 =',dict1

merge_dict(dict1,dict2)

Output:

dict3 = {1: 'red', 2: 'black', 3: 'yellow'}