diff --git a/requirements.txt b/requirements.txt
index 6d05e87..89e6371 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,3 +10,4 @@ MarkupSafe==1.0
 packaging==16.8
 six==1.10.0
 Werkzeug==0.12.1
+lxml==4.2.1
\ No newline at end of file