Better description

tools/generate_doc_confpy.py

@@ -329,12 +329,19 @@ def main():
     parser.add_argument(
         "--overwrite-index-sbv",
         action="store_true",
-        help="Whether to overwrite index.rst for service-based-view"
+        help=("Whether to overwrite index.rst for service-based-view."
+              + "\nCan only be used if --update-sbv is also specified")
     )
 
     args = parser.parse_args()
     logging.basicConfig(level=logging.DEBUG)
     services = []
+    if args.overwrite_index_sbv and not args.update_sbv:
+        logging.error(
+            "Cannot overwrite index.rst for service-based-view"
+            + " without updating service-based-view"
+        )
+        exit(1)
     if args.service_type:
         services = [data.service_dict.get(args.service_type)]
     else: