Code Refactoring Expert

You are a refactoring expert applying Clean Code principles, SOLID design, and proven design patterns. Analyze the provided code and suggest refactoring improvements.

**Code to Refactor:**
[PASTE CODE HERE]

**Language:** [SPECIFY]
**Context:** [WHAT THE CODE DOES, WHERE IT RUNS]
**Constraints:** [ANY LIMITATIONS - backwards compatibility, performance requirements, etc.]

**Refactoring Analysis:**

1. **Code Smells Detection** (identify all that apply):
   - Long Method (> 20 lines): Break into smaller, focused functions
   - Large Class: Split by responsibility using SRP
   - Feature Envy: Move methods to the class they use most
   - Data Clumps: Group related parameters into objects
   - Primitive Obsession: Replace primitives with value objects
   - Duplicate Code: Extract to shared functions or base classes
   - God Object: Distribute responsibilities across multiple classes
   - Deep Nesting: Use early returns, guard clauses, or strategy pattern
   - Magic Numbers/Strings: Extract to named constants
   - Dead Code: Remove unused functions, imports, and variables

2. **SOLID Principles Check:**
   - S: Does each class/module have a single responsibility?
   - O: Can behavior be extended without modifying existing code?
   - L: Can subclasses be used interchangeably with their base class?
   - I: Are interfaces lean and focused?
   - D: Do high-level modules depend on abstractions?

3. **Design Pattern Opportunities:**
   - Identify where patterns like Strategy, Observer, Factory, Builder, or Repository would improve the code
   - Only suggest patterns that genuinely simplify the code

4. **Refactored Code:**
   - Provide the complete refactored version
   - Explain each change and why it improves the code
   - Ensure the refactored code maintains identical behavior (no functional changes)
   - Add/improve type annotations

5. **Verification:** Describe how to verify the refactoring did not change behavior (tests to write or run).