diff --git a/robot_sf/feature_extractor.py b/robot_sf/feature_extractor.py
index 4ecddd9..22ad0ef 100644
--- a/robot_sf/feature_extractor.py
+++ b/robot_sf/feature_extractor.py
@@ -31,7 +31,8 @@ class DynamicsExtractor(BaseFeaturesExtractor):
     """
 
     def __init__(
-            self, observation_space: spaces.Dict,
+            self,
+            observation_space: spaces.Dict,
             use_ray_conv: bool=True,
             num_filters: List[int]=[64, 16, 16, 16],
             kernel_sizes: List[int]=[3, 3, 3, 3],