diff --git a/flatland/envs/rail_generators.py b/flatland/envs/rail_generators.py
index 028928aeec2c08c7b9035d875a874987dce79896..3e90128c74bda860d8a4c75d71652071660482a3 100644
--- a/flatland/envs/rail_generators.py
+++ b/flatland/envs/rail_generators.py
@@ -343,6 +343,17 @@ def random_rail_generator(cell_type_relative_proportion=[1.0] * 11, seed=1) -> R
                 template = [template[-1]] + template[:-1]
 
         def get_matching_templates(template):
+            """
+            Returns a list of possible transition maps for a given template
+            
+            Parameters:
+            ------
+            template:List[int]
+
+            Returns:
+            ------
+            List[int]
+            """
             ret = []
             for i in range(len(transitions_templates_)):
                 is_match = True
diff --git a/notebooks/simple_example1_env_from_tuple.ipynb b/notebooks/simple_example1_env_from_tuple.ipynb
index 2d13585156b447fe4f9eed07834b3dc04ccf84d6..317a5b63ef171691c0324d38d82ad543e295155c 100644
--- a/notebooks/simple_example1_env_from_tuple.ipynb
+++ b/notebooks/simple_example1_env_from_tuple.ipynb
@@ -10,9 +10,21 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 2,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "ename": "SystemError",
+     "evalue": "Parent module '' not loaded, cannot perform relative import",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mSystemError\u001b[0m                               Traceback (most recent call last)",
+      "\u001b[0;32m<ipython-input-2-b6a25a9cfbbb>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;32mfrom\u001b[0m \u001b[0;34m.\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mflatland\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0menvs\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mrail_generators\u001b[0m \u001b[0;32mimport\u001b[0m \u001b[0mrail_from_manual_specifications_generator\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m      2\u001b[0m \u001b[0;32mfrom\u001b[0m \u001b[0mflatland\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0menvs\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mobservations\u001b[0m \u001b[0;32mimport\u001b[0m \u001b[0mTreeObsForRailEnv\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      3\u001b[0m \u001b[0;32mfrom\u001b[0m \u001b[0mflatland\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0menvs\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mrail_env\u001b[0m \u001b[0;32mimport\u001b[0m \u001b[0mRailEnv\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      4\u001b[0m \u001b[0;32mfrom\u001b[0m \u001b[0mflatland\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mutils\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mrendertools\u001b[0m \u001b[0;32mimport\u001b[0m \u001b[0mRenderTool\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      5\u001b[0m \u001b[0;32mfrom\u001b[0m \u001b[0mPIL\u001b[0m \u001b[0;32mimport\u001b[0m \u001b[0mImage\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
+      "\u001b[0;31mSystemError\u001b[0m: Parent module '' not loaded, cannot perform relative import"
+     ]
+    }
+   ],
    "source": [
     "from flatland.envs.rail_generators import rail_from_manual_specifications_generator\n",
     "from flatland.envs.observations import TreeObsForRailEnv\n",
@@ -24,7 +36,9 @@
   {
    "cell_type": "code",
    "execution_count": 2,
-   "metadata": {},
+   "metadata": {
+    "collapsed": true
+   },
    "outputs": [],
    "source": [
     "specs = [[(0, 0), (0, 0), (0, 0), (0, 0), (0, 0), (0, 0)],\n",
@@ -83,7 +97,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.3"
+   "version": "3.5.2"
   },
   "latex_envs": {
    "LaTeX_envs_menu_present": true,
diff --git a/notebooks/simple_example2_generate_random_rail.ipynb b/notebooks/simple_example2_generate_random_rail.ipynb
index 19b854ee15d8dd1e19361f58a552eba617b19b67..bfa2c877ef0ecec8c596592c13c08db287661c78 100644
--- a/notebooks/simple_example2_generate_random_rail.ipynb
+++ b/notebooks/simple_example2_generate_random_rail.ipynb
@@ -88,7 +88,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.5"
+   "version": "3.5.2"
   },
   "latex_envs": {
    "LaTeX_envs_menu_present": true,