GPT2 tokenizer should not output token type IDs (#5546)

* GPT2 tokenizer should not output token type IDs

* Same for OpenAIGPT

src/transformers/tokenization_gpt2.py

@@ -137,6 +137,7 @@ class GPT2Tokenizer(PreTrainedTokenizer):
     vocab_files_names = VOCAB_FILES_NAMES
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
     max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
+    model_input_names = ["attention_mask"]
 
     def __init__(
         self,
@@ -330,6 +331,7 @@ class GPT2TokenizerFast(PreTrainedTokenizerFast):
     vocab_files_names = VOCAB_FILES_NAMES
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
     max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
+    model_input_names = ["attention_mask"]
 
     def __init__(
         self,

src/transformers/tokenization_openai.py

@@ -96,6 +96,7 @@ class OpenAIGPTTokenizer(PreTrainedTokenizer):
     vocab_files_names = VOCAB_FILES_NAMES
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
     max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
+    model_input_names = ["attention_mask"]
 
     def __init__(self, vocab_file, merges_file, unk_token="<unk>", **kwargs):
         super().__init__(unk_token=unk_token, **kwargs)
@@ -261,6 +262,7 @@ class OpenAIGPTTokenizerFast(PreTrainedTokenizerFast):
     vocab_files_names = VOCAB_FILES_NAMES
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
     max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
+    model_input_names = ["attention_mask"]
 
     def __init__(self, vocab_file, merges_file, unk_token="<unk>", **kwargs):
         kwargs.setdefault("unk_token", unk_token)