Good question! You could take a look at my newer article How to Build a Stock Tracker with Plotly and Flask where the callback function simple reads the value of each input and then constructs a response.

https://medium.datadriveninvestor.com/how-to-build-a-stocker-tracker-with-plotly-and-flask-8bf677f723af

A more generic solution would be to have a list in input ids which the callback function would loop through getting each value and construction a response from them - the list could be constructed directly in JS on the client side or in Python on the server and transferred to the template when the page is loaded

Technology, data science and programming. LinkedIn: https://www.linkedin.com/in/alan-jones-032699100