Refactor the deserialiser to improve readability and simplify logic

[gayal-r]

Hello Team/Markus Fuchs,

I have created this PR to improve the readability of the deserialiser and also simply the logic going on in there.

1. Made indexes of the array explicitly readout in code (Specific index of the states array mapping to certain field is now apparent in the code).
2. Simplifications around overall logic being used to deserialise the response from API.

All the tests in the project passed successfully.

I look forward to your review and feedback or merge altogether, thanks!