diff --git a/requirements.txt b/requirements.txt
index 18f13f0..118885e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,7 @@
 coverage==4.4.1
 mypy==0.521
+PyExecJS==1.4.1
 pymongo==3.5.1
+six==1.10.0
 Transcrypt==3.6.50
 typed-ast==1.0.4