From 0e60535121800081182aff2735141927b85ba623 Mon Sep 17 00:00:00 2001
From: Alexey Zakharenkov <a-zakh@yandex.ru>
Date: Thu, 29 Sep 2022 20:24:03 +0300
Subject: [PATCH] Take into account that City.validate() method may never be
 called for a city - in case a CriticalValidationError occured

---
 subway_structure.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/subway_structure.py b/subway_structure.py
index ef8226b..897f527 100644
--- a/subway_structure.py
+++ b/subway_structure.py
@@ -1740,10 +1740,11 @@ class City:
 
     @property
     def is_good(self):
-        assert self.validate_called, (
-            "You mustn't refer to City.is_good property before calling "
-            "the City.validate() method."
-        )
+        if not (self.errors or self.validate_called):
+            raise RuntimeError(
+                "You mustn't refer to City.is_good property before calling "
+                "the City.validate() method unless an error already occurred."
+            )
         return len(self.errors) == 0
 
     def get_validation_result(self):