Do you want your code to react to a computer event?
There is a function called accept that is a method of a ShowBase class. You can use this function to attach an event (i.e, mouse press, key press, etc) to a function that you write.
self.accept("arrow_up-up", self.fn, ["forward", 0])
This line of code tells Panda that, when the up arrow is released, to run the function
self.fn is any function that you write yourself as part of your animation. This is not a real function.
You can look up the various events on the Panda3D website.