diff --git a/moto/elbv2/models.py b/moto/elbv2/models.py
index 398a63481..b30ab5764 100644
--- a/moto/elbv2/models.py
+++ b/moto/elbv2/models.py
@@ -113,7 +113,6 @@ class FakeListener(BaseModel):
     def rules(self):
         return self._non_default_rules + [self._default_rule]
 
-
     def register(self, rule):
         self._non_default_rules.append(rule)
         self._non_default_rules = sorted(self._non_default_rules, key=lambda x: x.priority)
@@ -125,7 +124,7 @@ class FakeRule(BaseModel):
         self.listener_arn = listener_arn
         self.arn = listener_arn.replace(':listener/', ':listener-rule/') + "/%s" % (id(self))
         self.conditions = conditions
-        self.priority = priority # int or 'default'
+        self.priority = priority  # int or 'default'
         self.actions = actions
         self.is_default = is_default
 
@@ -220,7 +219,7 @@ class ELBv2Backend(BaseBackend):
     def create_rule(self, listener_arn, conditions, priority, actions):
         listeners = self.describe_listeners(None, [listener_arn])
         if not listeners:
-            raise ListenerNotFound()
+            raise ListenerNotFoundError()
         listener = listeners[0]
 
         # validate conditions
@@ -450,7 +449,6 @@ class ELBv2Backend(BaseBackend):
         rule.actions = actions
         return [rule]
 
-
     def register_targets(self, target_group_arn, instances):
         target_group = self.target_groups.get(target_group_arn)
         if target_group is None:
diff --git a/moto/elbv2/responses.py b/moto/elbv2/responses.py
index a798d1e41..5dcc78a75 100644
--- a/moto/elbv2/responses.py
+++ b/moto/elbv2/responses.py
@@ -131,7 +131,7 @@ class ELBV2Response(BaseResponse):
         all_rules = self.elbv2_backend.describe_rules(listener_arn, rule_arns)
         all_arns = [rule.arn for rule in all_rules]
         all_arns = [base64.urlsafe_b64encode(bytes(rule.arn, 'UTF-8')) for rule in all_rules]
-        page_size = self._get_int_param('PageSize', 50) # set 50 for temporary
+        page_size = self._get_int_param('PageSize', 50)  # set 50 for temporary
 
         marker = self._get_param('Marker')
         if marker:
@@ -905,8 +905,7 @@ DESCRIBE_TARGET_HEALTH_TEMPLATE = """<DescribeTargetHealthResponse xmlns="http:/
   </ResponseMetadata>
 </DescribeTargetHealthResponse>"""
 
-
-SET_RULE_PRIORITIES_TEMPLATE="""<SetRulePrioritiesResponse xmlns="http://elasticloadbalancing.amazonaws.com/doc/2015-12-01/">
+SET_RULE_PRIORITIES_TEMPLATE = """<SetRulePrioritiesResponse xmlns="http://elasticloadbalancing.amazonaws.com/doc/2015-12-01/">
   <SetRulePrioritiesResult>
     <Rules>
       {% for rule in rules %}