d_3 = {'key1':'-', 'key2':{'nested_key1':'o', 'nested_key2':'x'}, 'key3':'o'}
How to extract 'x'?
Syntax for getting the value.
it's the same operation as getting a dictionary value, except that you need to do it twice.
d_3['key2']
gives you the value of key2, in other words that's your nested dictionary.
So d_3['key2']['nested_key2']
simply gives you the value of your nested_key2.
Have a nice day ;)