In Python, how would I pass an argument from the command line to a unittest function?

Here is the code so far… I know it's wrong.

```
class TestingClass(unittest.TestCase):

    def testEmails(self):
        assertEqual(email_from_argument, "my_email@example.com")

if __name__ == "__main__":
    unittest.main(argv=[sys.argv[1]])
    email_from_argument = sys.argv[1]

```