......F.......F.

======================================================================

FAIL: testIntersect (tester.ProblemTests)

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Traceback (most recent call last):

  File ".../test.py", line 68, in testIntersect

    self.assertEqual(Interval(6, 11), Interval(None, 11).intersect(Interval(6, 12)))

AssertionError: Interval(6.0,11.0) != (6.0, 11.0)



======================================================================

FAIL: testSum (tester.ProblemTests)

----------------------------------------------------------------------

Traceback (most recent call last):

  File ".../test.py", line 103, in testSum

    self.assertEqual(Interval(6, None), Interval(6, 18) + Interval(18, None))

AssertionError: Interval(6.0,None) != Interval(6.0,18.0)



----------------------------------------------------------------------

Ran 16 tests in 0.006s



FAILED (failures=2)