message: Undefined name: import unittest in test_sgf_wrapper.py
  [flake8](http://flake8.pycqa.org) testing of on Python 3.7.0
  $ __flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics__
  ```
  ./tests/test_sgf_wrapper.py:166:5: F821 undefined name 'unittest'
  unittest.main()
  ^
  1     F821 undefined name 'unittest'
  1
  ```
diff: # See the License for the specific language governing permissions and
  # limitations under the License.
  +import unittest
  import go
  from sgf_wrapper import replay_sgf, translate_sgf_move, make_sgf
  