$ python fizzbuzz_test.py 
F
======================================================================
FAIL: test_FizzBuzz (__main__.TestFizzBuzz)
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Traceback (most recent call last):
  File "fizzbuzz_test.py", line 9, in test_FizzBuzz
    self.assertEqual(FizzBuzz(1), 1)
AssertionError: None != 1

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Ran 1 test in 0.000s

FAILED (failures=1)