diff --git a/agent/canvas.py b/agent/canvas.py
index cb939a0f3..9919fe1da 100644
--- a/agent/canvas.py
+++ b/agent/canvas.py
@@ -299,7 +299,7 @@ class Canvas(ABC):
                 pat = " => ".join([p.split(":")[0] for p in path[0:l]])
                 return pat + " => " + pat
 
-        return
+        return False
 
     def get_prologue(self):
         return self.components["begin"]["obj"]._param.prologue
diff --git a/agent/component/categorize.py b/agent/component/categorize.py
index ee398e493..118b7a8a2 100644
--- a/agent/component/categorize.py
+++ b/agent/component/categorize.py
@@ -82,6 +82,6 @@ class Categorize(Generate, ABC):
             if ans.lower().find(c.lower()) >= 0:
                 return Categorize.be_output(self._param.category_description[c]["to"])
 
-        return Categorize.be_output(self._param.category_description.items()[-1][1]["to"])
+        return Categorize.be_output(list(self._param.category_description.items())[-1][1]["to"])