How to fake a widget button "clicked" style with the keyboard key press?


I can not get an idea what is the easiest way to callback or something, to change the widget button style to pressed or clicked without actually CLICK on it, but with keyboard key attached.
Basically, I want to light up the button with the pressed key, same like I click on it. I could make it all with the style change, but I believe must be the fastest, cheaper way.
Here can be seen on gif: (Thanks and take care)

If you are using a button, it has a state of hover and so, but I believe your widget is not going to have just an ugly button so changing the style of the elements you want is the way to go as far as I know.