Add removal of decompressed pickle file

hub/city_model_structure/city.py

@@ -14,6 +14,7 @@ import math
 import pickle
 import sys
 import pathlib
+import os
 from pathlib import Path
 from typing import List, Union
 
@@ -309,7 +310,9 @@ class City:
     """
     with open(str(compressed_city_filename), 'rb') as source, open(str(destination_filename), 'wb') as destination:
       destination.write(bz2.decompress(source.read()))
-    return City.load(destination_filename)
+      loaded_city = City.load(destination_filename)
+    os.unlink(destination_filename)
+    return loaded_city
 
   def save(self, city_filename):
     """