Exercise for reference: 

Add a new pair of key (e.g. c ) and value (e.g. 3 ) to the dictionary and print out the new dictionary.

d = {"a": 1, "b": 2}

Answer: 

d = {"a": 1, "b": 2}
d["c"] = 3
print(d)

Explanation: 

Adding pairs of keys and values is straightforward, as you can see. Note, though, that you cannot fix the order of the dictionary items. Dictionaries are unordered collections of items.