Code Refactor for Speed and Readability

[pderrenger]

This Ultralytics PR refactors code to improve performance and readability. 🔄

Key changes include:

🚀 Optimized various functions for faster execution.
🧩 Simplified complex logic for better understanding and maintenance.
🗑️ Removed redundant code to streamline operations.
📚 Improved code structure and organization.

These changes aim to enhance the overall quality and efficiency of the code. 🌟

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

This PR improves the handling of default arguments in several functions within the YOLOv3 codebase.

📊 Key Changes

• yaml_save function update: Changed the default argument for data from an empty dictionary to None.
• log_model function update: Modified the default argument for metadata from an empty dictionary to None.
• construct_dataset function optimization: Simplified the initialization of the data_dict.

🎯 Purpose & Impact

• Prevent unintended behavior: Using None as the default value instead of an empty dictionary avoids shared mutable default arguments which could lead to unintended side-effects, making the code more robust and reliable.
• Cleaner code: These changes ensure that the initializations are concise and prevent potential bugs, making the code easier to maintain and understand.
• Improved efficiency: The refactor in construct_dataset reduces redundancy, making the code more efficient.

These updates enhance the overall reliability and readability of the code, benefiting both developers and users. 🚀🔧