diff --git a/pythainlp/gpt/gpt_neo.py b/pythainlp/gpt/gpt_neo.py
index 2695bc94b..6a7235e7f 100644
--- a/pythainlp/gpt/gpt_neo.py
+++ b/pythainlp/gpt/gpt_neo.py
@@ -12,19 +12,23 @@
 
 
 class ListDataset(Dataset):
-    def __init__(self, txt_list: List[str], tokenizer: GPT2Tokenizer, max_length: int):
+    def __init__(
+        self, txt_list: List[str], tokenizer: GPT2Tokenizer, max_length: int
+    ):
         self.input_ids = []
         self.attn_masks = []
         self.labels = []
         for txt in txt_list:
             encodings_dict = tokenizer(
-                '<|startoftext|>' + txt + '<|endoftext|>',
+                '<|start|>' + txt + '<|end|>',
                 truncation=True,
                 max_length=max_length,
                 padding="max_length"
             )
             self.input_ids.append(torch.tensor(encodings_dict['input_ids']))
-            self.attn_masks.append(torch.tensor(encodings_dict['attention_mask']))
+            self.attn_masks.append(
+                torch.tensor(encodings_dict['attention_mask'])
+            )
 
     def __len__(self):
         return len(self.input_ids)
@@ -34,7 +38,9 @@ def __getitem__(self, idx: int):
 
 
 class FewShot:
-    def __init__(self, model_dir: str, device: str = "cuda", size: str = "125M") -> None:
+    def __init__(
+        self, model_dir: str, device: str = "cuda", size: str = "125M"
+    ):
         """
         :param str model_dir: path of model dir
         :param str device: device
@@ -56,12 +62,14 @@ def init_model(self, size: str = "125M") -> None:
         self.pretrained = "EleutherAI/gpt-neo-"+str(size)
         self.tokenizer = GPT2Tokenizer.from_pretrained(
             self.pretrained,
-            bos_token='<|startoftext|>',
-            eos_token='<|endoftext|>',
+            bos_token='<|start|>',
+            eos_token='<|end|>',
             pad_token='<|pad|>'
         )
         self.tokenizer.save_pretrained(self.model_dir)
-        self.model = GPTNeoForCausalLM.from_pretrained(self.pretrained).to(self.device)
+        self.model = GPTNeoForCausalLM.from_pretrained(
+            self.pretrained
+        ).to(self.device)
         self.model.resize_token_embeddings(len(self.tokenizer))
 
     def load_model(self):
@@ -71,8 +79,8 @@ def load_model(self):
         self.model_dir = self.model_dir
         self.tokenizer = GPT2Tokenizer.from_pretrained(
             self.model_dir,
-            bos_token='<|startoftext|>',
-            eos_token='<|endoftext|>',
+            bos_token='<|start|>',
+            eos_token='<|end|>',
             pad_token='<|pad|>'
         )
         self.model = GPTNeoForCausalLM.from_pretrained(
@@ -168,7 +176,7 @@ def gen(
         :rtype: List[str]
         """
         self.generated = self.tokenizer(
-            '<|startoftext|>' + text, return_tensors="pt"
+            '<|start|>' + text, return_tensors="pt"
         ).input_ids.to(self.device)
         self.sample_outputs = self.model.generate(
             self.generated,
@@ -179,4 +187,8 @@ def gen(
             temperature=temperature,
             num_return_sequences=num_return_sequences
         )
-        return [self.tokenizer.decode(i, skip_special_tokens=True).replace('<|startoftext|>','') for i in self.sample_outputs]
+        return [
+            self.tokenizer.decode(
+                i, skip_special_tokens=True
+            ).replace("<|start|>", "") for i in self.sample_outputs
+        ]