From fc3e860b287f48baf264bbd9126c3d736fcf3c02 Mon Sep 17 00:00:00 2001
From: Y <yhuai@uci.edu>
Date: Sat, 28 Jan 2023 02:19:47 -0800
Subject: [PATCH] fix: StopSign Oracle

---
 framework/oracles/impl/StopSignOracle.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/framework/oracles/impl/StopSignOracle.py b/framework/oracles/impl/StopSignOracle.py
index c27858d..d01bf82 100644
--- a/framework/oracles/impl/StopSignOracle.py
+++ b/framework/oracles/impl/StopSignOracle.py
@@ -30,13 +30,14 @@ class StopSignOracle(OracleInterface):
     # Apollo: virtual_obstacle_id = STOP_SIGN_VO_ID_PREFIX + stop_sign_overlap.object_id;
     STOP_SIGN_VO_ID_PREFIX = "SS_"
 
-    checked = set()
+    checked: Set
 
     def __init__(self):
         self.violated_at_stop_sign_ids = set()
 
         self.parse_stop_sign_stop_line_string_on_map(MapParser.get_instance())
         self.reset_all_oracle_states()
+        self.checked = set()
 
     def get_interested_topics(self):
         """