[Tkinter] Button 'command' Argument Confusion

[gw1500se]

Thanks for the replies but that is exactly what I am doing. The subroutine 'submitData' exists and is not called anywhere else (one and only one reference). That is the confusing part. How is it getting called if not from the button and even if it is, why does clicking the button not call it again?

As for what the button returns, I am not using that reference anywhere so it doesn't matter. Indeed I did even equate it to a variable.