diff --git a/moto/autoscaling/models.py b/moto/autoscaling/models.py
index 84ae9c76b..88577433e 100644
--- a/moto/autoscaling/models.py
+++ b/moto/autoscaling/models.py
@@ -659,7 +659,11 @@ class AutoScalingBackend(BaseBackend):
         instance_states = []
         for group in self.autoscaling_groups.values():
             instance_states.extend(
-                [x for x in group.instance_states if not instance_ids or x.instance.id in instance_ids]
+                [
+                    x
+                    for x in group.instance_states
+                    if not instance_ids or x.instance.id in instance_ids
+                ]
             )
         return instance_states
 
diff --git a/tests/test_autoscaling/test_autoscaling.py b/tests/test_autoscaling/test_autoscaling.py
index 094708ec9..5cf3dc6ff 100644
--- a/tests/test_autoscaling/test_autoscaling.py
+++ b/tests/test_autoscaling/test_autoscaling.py
@@ -874,7 +874,9 @@ def test_describe_autoscaling_instances_instanceid_filter():
         for instance in response["AutoScalingGroups"][0]["Instances"]
     ]
 
-    response = client.describe_auto_scaling_instances(InstanceIds=instance_ids[0:2])  # Filter by first 2 of 5
+    response = client.describe_auto_scaling_instances(
+        InstanceIds=instance_ids[0:2]
+    )  # Filter by first 2 of 5
     len(response["AutoScalingInstances"]).should.equal(2)
     for instance in response["AutoScalingInstances"]:
         instance["AutoScalingGroupName"].should.equal("test_asg")