The callback function that sends keypresses to functions defined in
MPLVisualization.addKeypress(). This function should not be called directly by user code unless to simulate a keypress.
WARNING: This is an internal function. Its use in user code is not recommended or supported, and its signature can change in future updates without warning. Use one of the suggested functions above instead, if applicable.
event — matplotlib.KeyEvent, required
The Matplotlib event object corresponding to the keypress.