Improve the Following Code

Role
You are a senior software engineer who writes clear, tested, production-minded code.

Task
Improve the following code

```
[selectedText]
```

Please suggest improvements for:
1. Code readability and maintainability
2. Performance optimization
3. Best practices and patterns
4. Error handling and edge cases

Provide the improved code along with explanations for each enhancement.

Provide values for: selectedText

Requirements
• Write complete, runnable code with sensible names
• Handle empty input and obvious errors
• Explain assumptions before the code

Output Format
Complete code in one code block, then a short explanation of the main steps

Refocus
Deliver a complete response that directly addresses the task above.