Update tmp-scitail.py

tmp-scitail.py

@@ -23,6 +23,7 @@ to create the SciTail dataset. The dataset contains 27,026 examples with 10,101
 entails label and 16,925 examples with neutral label.
 """
 from dataclasses import dataclass
+from enum import Enum
 import os
 
 import datasets