WIP: [TM-13] Implement parseValue

Description

Implement parseValue and use it instead of stub 🤷 .

Related issue(s)

https://issues.serokell.io/issue/TM-13

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Related changes (conditional)

• Tests

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  • If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.

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    • README
    • Haddock

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