diff --git a/zadanie_1.py b/zadanie_1.py
index 3b59b0c..6bad1a4 100644
--- a/zadanie_1.py
+++ b/zadanie_1.py
@@ -44,3 +44,17 @@ def validate_orders(orders: list[dict]) -> list[dict]:
             order['item_name'].strip() != ''):
             valid_orders.append(order)
     return valid_orders
+
+
+# 3. Группировка заказов по пользователям
+def group_by_user(orders: list[dict]) -> dict[int, list[dict]]:
+    """
+    Группирует заказы по user_id.
+    """
+    grouped = {}
+    for order in orders:
+        uid = order['user_id']
+        if uid not in grouped:
+            grouped[uid] = []
+        grouped[uid].append(order)
+    return grouped
\ No newline at end of file