diff --git a/spacy/tokens/span.pyx b/spacy/tokens/span.pyx
index 0435f9260..1c316c8ea 100644
--- a/spacy/tokens/span.pyx
+++ b/spacy/tokens/span.pyx
@@ -801,7 +801,7 @@ cdef class Span:
             if label != self.span_c().label :
                 old_label = self.span_c().label
                 self.span_c().label = label
-                new = Underscore(Underscore.span_extensions, self, start=self.span_c().start_char, end=self.span_c().end_char, label = self.label, kb_id = self.kb_id, span_id=self.id)
+                new = Underscore(Underscore.span_extensions, self, start=self.span_c().start_char, end=self.span_c().end_char, label=self.label, kb_id=self.kb_id, span_id=self.id)
                 old = Underscore(Underscore.span_extensions, self, start=self.span_c().start_char, end=self.span_c().end_char, label=old_label, kb_id=self.kb_id, span_id=self.id)
                 Underscore._replace_keys(old, new)
             else: