Function From Requirements

Fill these in and the prompt below updates as you type. Anything you leave blank stays as a placeholder.

Write a {{language}} function that {{what_it_should_do}}.

Requirements:
- Input: {{input_spec}}
- Output: {{output_spec}}
- Edge cases to handle: {{edge_cases}}
- Performance constraint: {{performance_constraint}}

Include: type annotations/hints, a docstring with parameters and return type, and 3 unit test cases covering normal input, edge case, and error case.

Follow {{style_guide}} conventions.