diff --git a/termstr/termstr.py b/termstr/termstr.py
index e4bd21b..77a5f0b 100644
--- a/termstr/termstr.py
+++ b/termstr/termstr.py
@@ -414,7 +414,7 @@ class TermStr(collections.UserString):
         return self.transform_style(lambda style: style.bg_color_(bg_color))
 
     def invert(self):
-        return self.transform_style(CharStyle.invert_)
+        return self.transform_style(CharStyle.invert)
 
     def as_html(self):
         result = []