maybe fixed byte strings thing?

proof-pile.py

@@ -186,7 +186,7 @@ class ProofPile(datasets.GeneratorBasedBuilder):
         key = 0 
         if self.config.name in self.archived_configs: 
             for name, obj in data_files: 
-                text = obj.read()
+                text = obj.read().decode()
                 # Yields examples as (key, example) tuples
                 yield key, {
                     "config": self.config.name,