import re\n\ndef test_suite():\n    test_cases = ["a.b@example.com", "99@example.com", "user@example.co.uk", "test@test.test", "jane.doe@example.org", \n                    "abc123@example.com", "user123@example.com.au", "invalid@example.com_"]\n    valid_email_regex = \^[_a-z0-9-]+(\\.[_a-z0-9-]+)*@[a-z0-9-]+(\\.[a-z0-9-]+)*(\\.[a-z]{2,4})$\\n    for test_case in test_cases:\n        if re.match(valid_email_regex, test_case):\n            print(f"{test_case} is a valid email address.")\n        else:\n            print(f"{test_case} is not a valid email address.")\n    \nif __name__ == "__main__":\n    test_suite()
Create a test suite in Python to check if an input string is a valid email address.?