diff --git a/flatland/envs/observations.py b/flatland/envs/observations.py
index 8c3f260ba83e91e7657b7a0b3f8a70c5d228f9b1..03b8d56e0ee6d458598aea3fc087fefa99e68523 100644
--- a/flatland/envs/observations.py
+++ b/flatland/envs/observations.py
@@ -557,42 +557,6 @@ class TreeObsForRailEnv(ObservationBuilder):
                                         prompt=prompt_[children],
                                         current_depth=current_depth + 1)
 
-    def split_tree(self, tree, num_features_per_node=8, current_depth=0):
-        """
-
-        :param tree:
-        :param num_features_per_node:
-        :param prompt:
-        :param current_depth:
-        :return:
-        """
-
-        if len(tree) < num_features_per_node:
-            return [], [], []
-
-        depth = 0
-        tmp = len(tree) / num_features_per_node - 1
-        pow4 = 4
-        while tmp > 0:
-            tmp -= pow4
-            depth += 1
-            pow4 *= 4
-        child_size = (len(tree) - num_features_per_node) // 4
-        tree_data = tree[:4].tolist()
-        distance_data = [tree[4]]
-        agent_data = tree[5:num_features_per_node].tolist()
-        for children in range(4):
-            child_tree = tree[(num_features_per_node + children * child_size):
-                              (num_features_per_node + (children + 1) * child_size)]
-            tmp_tree_data, tmp_distance_data, tmp_agent_data = self.split_tree(child_tree,
-                                                                               num_features_per_node,
-                                                                               current_depth=current_depth + 1)
-            if len(tmp_tree_data) > 0:
-                tree_data.extend(tmp_tree_data)
-                distance_data.extend(tmp_distance_data)
-                agent_data.extend(tmp_agent_data)
-        return tree_data, distance_data, agent_data
-
     def _set_env(self, env):
         self.env = env
         if self.predictor:
diff --git a/notebooks/Scene_Editor.ipynb b/notebooks/Scene_Editor.ipynb
index abfe62204686b47a0c311fc2cf8e02b3da3d7a7a..a36b4e159a75edd2d18a5f7ed42ec41dbc5b9515 100644
--- a/notebooks/Scene_Editor.ipynb
+++ b/notebooks/Scene_Editor.ipynb
@@ -111,7 +111,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.8"
+   "version": "3.6.5"
   },
   "latex_envs": {
    "LaTeX_envs_menu_present": true,