how can I append a specific key in dictionary code example

Example 1: python dict append

default_data = {'item1': 1,
                'item2': 2,
          	    }

default_data.update({'item3': 3})
# or
default_data['item3'] = 3

Example 2: dictionary append value python

d = {1:2}
d.update({2: 4})
print(d) # {1: 2, 2: 4}