Added warning-distanc_map cannot be saved

flatland/envs/rail_env.py

@@ -712,9 +712,11 @@ class RailEnv(Environment):
                     with open(filename, "wb") as file_out:
                         file_out.write(self.get_full_state_dist_msg())
                 else:
-                    raise Exception("Unable to save distance map")
+                    print("[WARNING] Unable to save the distance map for this environment, as none was found !")
+
             else:
-                raise Exception("Unable to save distance map")
+                print("[WARNING] Unable to save the distance map for this environment, as none was found !")
+
         else:
             with open(filename,"wb") as file_out:
                 file_out.write(self.get_full_state_msg())

notebooks/simple_example1_env_from_tuple.ipynb

@@ -83,7 +83,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.8"
+   "version": "3.7.3"
   },
   "latex_envs": {
    "LaTeX_envs_menu_present": true,