Update tacred.py

tacred.py

@@ -72,6 +72,11 @@ Note 2: This Datasetreader changes the offsets of the following fields, to confo
 - subj_end to subj_end + 1 (make end offset exclusive)
 - oj_end to oj_end + 1 (make end offset exclusive)
 - stanford_head to stanford_head - 1 (make head offsets 0-based)
+
+It also changes the names of some fields:
+- token -> tokens
+- stanford_ner -> ner_tags
+- stanford_pos -> pos_tags
 """
 
 _HOMEPAGE = "https://nlp.stanford.edu/projects/tacred/"
@@ -134,6 +139,33 @@ _CLASS_LABELS = [
     "per:title",
 ]
 
+_NER_CLASS_LABELS = [
+    "LOCATION",
+    "ORGANIZATION",
+    "PERSON",
+    "DATE",
+    "MONEY",
+    "PERCENT",
+    "TIME",
+    "CAUSE_OF_DEATH",
+    "CITY",
+    "COUNTRY",
+    "CRIMINAL_CHARGE",
+    "EMAIL",
+    "HANDLE",
+    "IDEOLOGY",
+    "NATIONALITY",
+    "RELIGION",
+    "STATE_OR_PROVINCE",
+    "TITLE",
+    "URL",
+    "NUMBER",
+    "ORDINAL",
+    "MISC",
+    "DURATION",
+    "O"
+]
+
 
 def convert_ptb_token(token: str) -> str:
     """Convert PTB tokens to normal tokens"""
@@ -181,7 +213,7 @@ class Tacred(datasets.GeneratorBasedBuilder):
                 "tokens": datasets.Sequence(datasets.Value("string")),
                 "subj_start": datasets.Value("int32"),
                 "subj_end": datasets.Value("int32"),
-                "subj_type": datasets.Value("string"),
+                "subj_type": datasets.ClassLabel(names=_NER_CLASS_LABELS),
                 "obj_start": datasets.Value("int32"),
                 "obj_end": datasets.Value("int32"),
                 "obj_type": datasets.Value("string"),