move init of counter to __init__

Author: joshuadavidthomas

tests/utils.py

@@ -4,21 +4,22 @@
 
 
 class SequenceGenerator:
-    _instance = None
-    _lock = Lock()
+    _instance: SequenceGenerator | None = None
+    _lock: Lock = Lock()
+    _counter: int
 
-    def __init__(self):
-        self._counter = 1
+    def __init__(self) -> None:
+        if not hasattr(self, "_counter"):
+            self._counter = 1
 
-    def __new__(cls):
+    def __new__(cls) -> SequenceGenerator:
         if cls._instance is None:
             with cls._lock:
                 if cls._instance is None:
                     cls._instance = super().__new__(cls)
-                    cls._instance._counter = 1
         return cls._instance
 
-    def next(self):
+    def next(self) -> int:
         with self._lock:
             current = self._counter
             self._counter += 1