Currently, unittest setUpClass and tearDownClass methods are incorrectly called from within its core.

```
class TestUltrasonicEnv(unittest.TestCase):

    def setUpClass(cls):
        pass
    

    def tearDownClass(cls):
        pass
```

Traceback (the same for teadDownClass)
```
  File "/home/dizcza/anaconda3/envs/robotsim/lib/python3.7/unittest/suite.py", line 163, in _handleClassSetUp
    setUpClass()
TypeError: setUpClass() missing 1 required positional argument: 'cls'
```

The traceback is self-descriptive.