diff --git a/requirements.txt b/requirements.txt
index 3585b6a..9b68a3c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -12,4 +12,5 @@ jupyter
 jupyter_contrib_nbextensions
 notebook<7.0.0
 nbconvert<7.0.0
+lxml_html_clean
 psutil