fixed offset error

tacred.py

@@ -265,5 +265,5 @@ class Tacred(datasets.GeneratorBasedBuilder):
                     "pos_tags": example["stanford_pos"],
                     "ner_tags": example["stanford_ner"],
                     "stanford_deprel": example["stanford_deprel"],
-                    "stanford_head": example["stanford_head"] - 1,  # make offsets 0-based
+                    "stanford_head": [head - 1 for head in example["stanford_head"]]  # make offsets 0-based
                 }