catch ForeignKey delete exception on city

apps/location/views/back.py

@@ -1,5 +1,6 @@
 """Location app views."""
 from django.contrib.postgres.fields.jsonb import KeyTextTransform
+from django.db.models.deletion import ProtectedError
 from rest_framework import generics, status
 from rest_framework.response import Response
 from rest_framework.views import APIView
@@ -167,6 +168,13 @@ class CityRUDView(common.CityViewMixin, generics.RetrieveUpdateDestroyAPIView):
         IsGuest,
     )
 
+    def delete(self, request, *args, **kwargs):
+        try:
+            return self.destroy(request, *args, **kwargs)
+        except ProtectedError:
+            from rest_framework.serializers import ValidationError
+            raise ValidationError({'detail': 'City couldn’t be deleted. Some objects has this city'})
+
 
 # Region
 class RegionListCreateView(common.RegionViewMixin, generics.ListCreateAPIView):