Update model.py

model.py

@@ -90,7 +90,8 @@ class Model:
     def load_controlnet_weight(self, task_name: str) -> None:
         if task_name == self.task_name:
             return
-        del self.pipe.controlnet
+        if 'controlnet' in self.pipe.__dict__:
+            del self.pipe.controlnet
         torch.cuda.empty_cache()
         gc.collect()
         model_id = CONTROLNET_MODEL_IDS[task_name]