Update CrossSum.py

CrossSum.py

@@ -143,6 +143,7 @@ class Crosssum(datasets.GeneratorBasedBuilder):
     def _generate_examples(self, filepath):
         """Yields examples as (key, example) tuples."""
         with open(filepath, encoding="utf-8") as f:
+            idx_ = -1
             for idx_, row in enumerate(f):
                 data = json.loads(row)
                 yield idx_, {
@@ -151,3 +152,12 @@ class Crosssum(datasets.GeneratorBasedBuilder):
                     "summary": data["summary"],
                     "text": data["text"],
                 }
+
+            # empty splits for extremely low-resource pairs
+            if idx_ == -1:
+                yield 0, {
+                    "source_url": "",
+                    "target_url": "",
+                    "summary": "",
+                    "text": "",
+                }