This syntax is new since Python 3.5. If we have two dictionaries and want to merge them, we can use curly braces and double asterisks for both dictionaries. So here dictionary 1 has a name and an age, and dictionary 2 also has the name and then the city. After merging with this concise syntax our final dictionary has all 3 keys in it.
d1 = {'name': 'Alex', 'age': 25}
d2 = {'name': 'Alex', 'city': 'New York'}
merged_dict = {**d1, **d2}
print(merged_dict) # {'name': 'Alex', 'age': 25, 'city': 'New York'}