Call backs does not display trace

I am trying to update the graph using callback. For some reason nothing seems to appear in the figure.
I have attached the code and the sample screenshot.

Try printing


inside your “changegraph()” function, before you return the data. See what that gives you.

Thank you for getting back. When I print df[value] I get the series I want to plot. But, the plot does not appear in the app.

Returned the figure this way, and the callback seems to work.
Pls find the figure attached. But what difference does it make anyway