Update characters.py

characters.py

@@ -63,8 +63,10 @@ class Characters(datasets.GeneratorBasedBuilder):
 
     def _generate_examples(self, images):
         """Yields examples."""
+        idx = 0
         for filepath, image in images:
-            yield {
+            yield idx, {
                 "image": {"path": filepath, "bytes": image.read()},
                 "text" : filepath,
-            }
+            }
+            idx+=1