use iterator during weight loading

train.py

@@ -622,7 +622,7 @@ def load_and_quantize_parallel(name_param, model, **kwargs):
             n_workers = min(left, right)
             if rank == 0 and args['verbose']:
                 print_func(f"Using n_workers: {n_workers} for loading")
-            parallel(load_and_quantize_parallel, weights.items(), n_workers=n_workers, threadpool=True,
+            parallel(load_and_quantize_parallel, iter(weights.items()), n_workers=n_workers, threadpool=True,
                      model=model, dtype=torch_dtype, device=local_rank, skip_names=load_param_skip_names,
                      is_meta_rank=(args["low_memory"] and rank!=0), verbose=args["verbose"], quant_method=quant_method)
         if rank == 0 and args["verbose"]: