I am trying to create an app in jira,Should I add any external link to the html file when I used python code along with it?

I used python flask along with html to create an app for jira,I was able to upload the app successfully,but the app is not loading once installed in jira,should I add any link of any python program in the html file,For eg when we link a js to html,we add the link ‘’.This link only works when we use js,what should I do if I use python?