Write a function that removes duplicates while preserving order.

Write a Python function that removes duplicate values while preserving the original order.

Expected Answer

Use a set to track seen values and append unseen values to a result list.

Detailed Explanation

This checks whether you can balance correctness and readable Python. The key detail is preserving order instead of simply converting to a set.

Common Follow-up Questions

• What if values are unhashable?
• What is the time complexity?