Ignore import error.

.flake8

@@ -1,5 +1,5 @@
 [flake8]
 exclude = cmlutils,*venv*,.git,.eggs,__pycache__,docs/source/conf.py,old,build,dist
-ignore = E731
+ignore = E731, E402
 max-complexity = 20
 max-line-length = 140