Fix the flake8 errors

opentech/apply/tests/test_workflow.py

@@ -32,6 +32,7 @@ class TestWorkflowCreation(SimpleTestCase):
         workflow = WorkflowFactory(num_stages=2)
         self.assertEqual(workflow.next(workflow.stages[0]), workflow.stages[1])
 
+
 class TestStageCreation(SimpleTestCase):
     def test_can_create_stage(self):
         name = 'the_stage'

opentech/apply/workflow.py

@@ -18,7 +18,7 @@ class Workflow(Iterable['Stage']):
         for i, stage in enumerate(self):
             if stage == current_stage:
                 try:
-                    return self.stages[i+1]
+                    return self.stages[i + 1]
                 except IndexError:
                     pass