Add stable_hash function for JSON objects

label_hash.py

@@ -0,0 +1,10 @@
+from __future__ import annotations
+
+import hashlib
+import json
+from typing import Any
+
+
+def stable_hash(obj: Any) -> str:
+    canonical = json.dumps(obj, ensure_ascii=False, separators=(",", ":"), sort_keys=True)
+    return hashlib.sha256(canonical.encode("utf-8")).hexdigest()[:16]