fix legacy code

Author: vmoens

test/test_collector.py

@@ -1576,7 +1576,12 @@ def create_env():
 
         # Create shared memory weight sync scheme
         weight_sync_scheme = SharedMemWeightSyncScheme()
-        weight_sync_scheme.register_shared_weights("policy", policy_weights)
+        # Use the new init_on_sender API with params_map
+        # All 3 workers share the same CPU weights in shared memory
+        weight_sync_scheme.init_on_sender(
+            model_id="policy",
+            params_map={0: policy_weights, 1: policy_weights, 2: policy_weights},
+        )
 
         collector_class = (
             MultiSyncDataCollector if not use_async else MultiaSyncDataCollector