adjust error message related to args.do_eval

examples/run_lm_finetuning.py

@@ -501,8 +501,8 @@ def main():
     if n_gpu > 0:
         torch.cuda.manual_seed_all(args.seed)
 
-    if not args.do_train and not args.do_eval:
-        raise ValueError("At least one of `do_train` or `do_eval` must be True.")
+    if not args.do_train:
+        raise ValueError("Training is currently the only implemented execution option. Please set `do_train`.")
 
     if os.path.exists(args.output_dir) and os.listdir(args.output_dir):
         raise ValueError("Output directory ({}) already exists and is not empty.".format(args.output_dir))