You are working on a Python function find_max(numbers) that returns the largest number in a list. The function is defined as follows: def find_max ( numbers ): if not numbers : return None max_num = numbers [ 0 ] for num in numbers [ 1 :]: if num > max_num : max_num = num return max_num To get comprehensive test suggestions from GitHub Copilot for edge cases, which approach should you take?