diff --git a/e2e/test_sources_oauth.py b/e2e/test_sources_oauth.py
index 01b29e056..5cbbccec8 100644
--- a/e2e/test_sources_oauth.py
+++ b/e2e/test_sources_oauth.py
@@ -81,7 +81,7 @@ class TestSourceOAuth(SeleniumTestCase):
                 interval=5 * 100 * 1000000,
                 start_period=1 * 100 * 1000000,
             ),
-            volumes={abspath(CONFIG_PATH): {"bind": "/config.yml", "mode": "ro",}},
+            volumes={abspath(CONFIG_PATH): {"bind": "/config.yml", "mode": "ro"}},
         )
         while True:
             container.reload()
diff --git a/passbook/flows/views.py b/passbook/flows/views.py
index f2c5e1622..5553291c3 100644
--- a/passbook/flows/views.py
+++ b/passbook/flows/views.py
@@ -85,15 +85,16 @@ class FlowExecutorView(View):
                 return self.handle_invalid_flow(exc)
         # We don't save the Plan after getting the next stage
         # as it hasn't been successfully passed yet
-        self.current_stage = self.plan.next()
+        next_stage = self.plan.next()
+        if not next_stage:
+            LOGGER.debug("f(exec): no more stages, flow is done.")
+            return self._flow_done()
+        self.current_stage = next_stage
         LOGGER.debug(
             "f(exec): Current stage",
             current_stage=self.current_stage,
             flow_slug=self.flow.slug,
         )
-        if not self.current_stage:
-            LOGGER.debug("f(exec): no more stages, flow is done.")
-            return self._flow_done()
         stage_cls = self.current_stage.type()
         self.current_stage_view = stage_cls(self)
         self.current_stage_view.args = self.args
diff --git a/passbook/policies/types.py b/passbook/policies/types.py
index 29ab69146..da956c75e 100644
--- a/passbook/policies/types.py
+++ b/passbook/policies/types.py
@@ -32,7 +32,7 @@ class PolicyResult:
     """Small data-class to hold policy results"""
 
     passing: bool
-    messages: Tuple[str]
+    messages: Tuple[str, ...]
 
     def __init__(self, passing: bool, *messages: str):
         self.passing = passing