You need to look for a JSON library in Python language, that would let you serialize and deserialize the JSON strings, to runtime objects.
If you're using Python 2, consider the following,
18.2. json — JSON encoder and decoder — Python 2.7.13 documentation[
^]. There is a sample demonstration of the package available on that page that you can use for your own project. There are encoders and decoders specified there, that you are interested in.
Once decoded from string, to an object, you can fetch the value of that property. Go through that link to learn more.