swift234

Remove unused import (recently introduced PEP8 regression)

PEP8 regressions can be found by running:

```
flake8 --ignore=E101,E111,E121,E122,E123,E124,E125,E126,E127,E128,E129,E131,E201,E202,E203,E222,E225,E226,E227,E231,E241,E251,E261,E262,E265,E301,E302,E303,E401,E501,E701,W191,W291,W293,W391 .
```

The ignores are minor PEP8 violations currently found in the repo. We ignore those.