Merge pull request #437 from jhao104/develop

[fix]  fix #401

requirements.txt

@@ -2,7 +2,7 @@ APScheduler==3.2.0
 werkzeug==0.11.15
 Flask==1.0
 requests==2.20.0
-lxml==3.7.2
+lxml==4.4.2
 PyExecJS==1.5.1
 click==7.0
 gunicorn==19.9.0