Refactored converter.py to handle convert logic only

[sue-lim]

Refactored converter.py to handle convert logic only

[FEATURE] Currency Script | Implement currency conversion logic in dedicated module #430

Summary

Refactored converter.py to streamline currency conversion logic using the CurrencyConverter class with a clearer structure and docstrings.

Description

This PR refactors the converter.py module to improve modularity, readability, and consistency. The changes focus on encapsulating currency conversion logic in a clean, testable way. Key updates include:

• Created a clean and minimal CurrencyConverter class.
• Simplified the convert() method using base currency (EUR) logic.
• Added input validation for currency codes.
• Included a manual test in the main block for direct debugging.
• Updated docstrings with compact, beginner-friendly versions.
• Ensured consistency with the structure used in currencies.py.

The changes are as follows:

• Refactored logic into CurrencyConverter class.
• Added basic error handling for invalid currency codes.
• Reduced redundancy, improved structure.
• Included inline docstrings and top-level module docstring.
• Manual test block under if name == "main" included for quick verification.

Checks

in the repository

• Made no changes that degrades the functioning of the repository
• Gave each commit a better title (unlike updated README.md)

in the PR

• Followed the format of the pull_request_template
• Made the Pull Request in a small level (for the creator's wellfare)
• Tested the changes you made, manually & via unittest

Thank You,

Sue

[sue-lim]

@DhanushNehru - please kindly approve :)