Enhance ECGXMLReader with Robust Error Handling and Augmented Lead SupportList confusion

[turkalpmd]

Description:
This pull request introduces several updates to the ECGXMLReader class, aimed at addressing common issues, improving functionality, and making the code more user-friendly.

Key updates include:

Improved Error Handling:
Added checks to gracefully handle missing or malformed fields like Waveform and LeadData.
The class now handles cases where Waveform is stored as a dictionary instead of a list, preventing crashes due to "list indices must be integers or slices" errors.

Flexibility in Data Structure:
The code now supports both list and dict formats for Waveform without requiring user intervention. This change resolves issues caused by inconsistent XML file structures.

Augmented Lead Support:
If only 8 leads are present, augmented leads (III, aVR, aVL, aVF) are calculated automatically, enhancing usability for datasets with limited information.

Documentation and Comments:
Added detailed docstrings for each method and inline comments for better readability and understanding of the code.

Why These Changes Matter:
Increased Reliability: The class can now handle a variety of XML structures without breaking.
User-Friendly: Informative logs and flexible handling of data structures make the class easier to use, even for those working with inconsistent datasets.
Broader Functionality: Support for augmented leads adds versatility to the class, ensuring it works with a wider range of data.
Collaboratively Built: These updates include insights gained from real-world challenges and community support.
Challenges Faced:
One particularly frustrating issue was the "list indices must be integers or slices" error. This occurred because some XML files stored Waveform as a dictionary instead of a list, leading to crashes when accessing it. It took me a few hours of debugging to identify and resolve the problem.

To address this, I modified the code to treat Waveform consistently as a list, regardless of its original format. This change ensures the class processes files correctly, no matter how the data is structured.

Acknowledgments:
I’d also like to give credit to ChatGPT for assisting me during the debugging process. It provided useful suggestions for handling edge cases and improving error handling. Collaboration with the tool helped refine this update into its current form.

Testing and Validation:
I’ve tested these changes extensively with a diverse set of ECG XML files, including ones with inconsistent structures and missing fields. The class now processes valid files successfully and logs issues for invalid ones, ensuring no data is lost during processing.

Your Feedback Matters:
I would love to hear your feedback on these changes. If there’s anything you think could be improved further or any additional features you’d like to see, please let me know. Your insights are invaluable in making this tool even better.

Thank you for reviewing this pull request – I hope it helps simplify your work and enhances your experience with ECGXMLReader. 😊