make create_from_arg_string fully general

for some reason putting it in LM and having it be inherited breaks
everything. should try to figure this out at some point.

lm_eval/models/gpt2.py

@@ -44,10 +44,10 @@ class GPT2LM(LM):
         #     self.gpt2 = nn.DataParallel(self.gpt2)
 
     @classmethod
-    def create_from_arg_string(cls, arg_string, **kwargs):
+    def create_from_arg_string(cls, arg_string, additional_config={}):
         args = utils.simple_parse_args_string(arg_string)
-        kwargs = {k: v for k, v in kwargs.items() if v is not None}
-        return cls(pretrained=args.get("pretrained", "gpt2"), **kwargs)
+        args2 = {k: v for k, v in additional_config.items() if v is not None}
+        return cls(**args, **args2)
 
     def loglikelihood(self, requests):
         new_reqs = []

lm_eval/models/gpt3.py

@@ -65,10 +65,10 @@ class GPT3LM(LM):
         openai.api_key = os.environ["OPENAI_API_SECRET_KEY"]
 
     @classmethod
-    def create_from_arg_string(cls, arg_string, **kwargs):
+    def create_from_arg_string(cls, arg_string, additional_config={}):
         args = utils.simple_parse_args_string(arg_string)
-        kwargs = {k: v for k, v in kwargs.items() if v is not None}
-        return cls(engine=args.get("engine", "davinci"), **kwargs)
+        args2 = {k: v for k, v in additional_config.items() if v is not None}
+        return cls(**args, **args2)
 
     def loglikelihood(self, requests):
         new_reqs = []

main.py

@@ -29,7 +29,9 @@ def main():
     random.seed(args.seed)
     np.random.seed(args.seed)
 
-    lm = models.get_model(args.model).create_from_arg_string(args.model_args, batch_size=args.batch_size, device=args.device)
+    lm = models.get_model(args.model).create_from_arg_string(args.model_args, {
+        'batch_size': args.batch_size, 'device': args.device
+    })
     
     if args.limit:
         print("WARNING: --limit SHOULD ONLY BE USED FOR TESTING. REAL METRICS SHOULD NOT BE COMPUTED USING LIMIT.")