diff --git a/opus_mt.py b/opus_mt.py
index 0ff5566..df14415 100644
--- a/opus_mt.py
+++ b/opus_mt.py
@@ -25,30 +25,31 @@ from towhee import register
 
 from transformers import AutoTokenizer, AutoModelForSeq2SeqLM
 
-class OpusMT()
+class OpusMT(NNOperator):
     """
     Opus-mt machine translation
     """
     def __init__(self, model_name: str):
         super().__init__()
         self.device = "cuda" if torch.cuda.is_available() else "cpu"
-        config = self.configs[model_name]  
+        config = self.configs()[model_name]  
         self.tokenizer = AutoTokenizer.from_pretrained(config['tokenizer'])
         self.model = AutoModelForSeq2SeqLM.from_pretrained(config['model'])
         self.model.to(self.device)
 
     def __call__(self, data): 
-        input_ids = tokenizer(data, return_tensors='pt', padding=True)['input_ids'].to(self.device)
-        outputs = model.generate(input_ids)
-        decoded = tokenizer.decode(outputs[0].detach().cpu(), skip_special_tokens=True)
+        input_ids = self.tokenizer(data, return_tensors='pt', padding=True)['input_ids'].to(self.device)
+        outputs = self.model.generate(input_ids)
+        decoded = self.tokenizer.decode(outputs[0].detach().cpu(), skip_special_tokens=True)
         return decoded
-~
-    def _configs(self):
-        config = {}
-        config['opus-mt-en-zh'] = {}
-        config['opus-mt-en-zh']['tokenizer'] = 'Helsinki-NLP/opus-mt-en-zh'
-        config['opus-mt-en-zh']['model'] = 'Helsinki-NLP/opus-mt-en-zh'
-
-        config['opus-mt-zh-en'] = {}
-        config['opus-mt-zh-en']['tokenizer'] = 'Helsinki-NLP/opus-mt-zh-en'
-        config['opus-mt-zh-en']['model'] = 'Helsinki-NLP/opus-mt-zh-en'
+
+    def configs(self):
+        configs = {}
+        configs['opus-mt-en-zh'] = {}
+        configs['opus-mt-en-zh']['tokenizer'] = 'Helsinki-NLP/opus-mt-en-zh'
+        configs['opus-mt-en-zh']['model'] = 'Helsinki-NLP/opus-mt-en-zh'
+
+        configs['opus-mt-zh-en'] = {}
+        configs['opus-mt-zh-en']['tokenizer'] = 'Helsinki-NLP/opus-mt-zh-en'
+        configs['opus-mt-zh-en']['model'] = 'Helsinki-NLP/opus-mt-zh-en'
+        return configs