diff --git a/spacy/gold.pyx b/spacy/gold.pyx
index 579010e6d..f9500dbb6 100644
--- a/spacy/gold.pyx
+++ b/spacy/gold.pyx
@@ -305,7 +305,7 @@ def read_json_file(loc, docs_filter=None, limit=None):
                     yield [paragraph.get('raw', None), sents]
 
 
-def _iob_to_biluo(tags):
+def iob_to_biluo(tags):
     out = []
     curr_label = None
     tags = list(tags)