1er

backend/app/services/__init__.py

@@ -0,0 +1 @@
+"""Services utilitaires côté backend."""

backend/app/services/pricing.py

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+from __future__ import annotations
+
+
+def price_trend(prices: list[float]) -> str:
+    if not prices:
+        return "stable"
+    first, last = prices[0], prices[-1]
+    if last > first:
+        return "up"
+    if last < first:
+        return "down"
+    return "stable"