resolve TypeError

lm_eval/models/gpt2.py

@@ -25,7 +25,8 @@ class HFLM(BaseLM):
 
         # pretrained tokenizer for neo is broken for now so just hard-coding this to gpt2
         self.tokenizer = transformers.AutoTokenizer.from_pretrained(
-            pretrained if tokenizer is None else tokenizer, revision=revision, subfolder=subfolder)
+            pretrained if tokenizer is None else tokenizer,
+            revision=revision + ("/" + subfolder if subfolder is not None else ""))
 
         # assert isinstance(self.tokenizer, (
         #     transformers.GPT2Tokenizer, transformers.GPT2TokenizerFast,