$ python keyevents.py 

* Below is the output for when alt-esc is pressed. state-changed showing appears.
onKeyPressOrRelease: pressed
	hw_code: 64
	event_string: Alt_L
	modifiers: 0
	id: 65513
	timestamp: 10009360
	is_text: True
object:state-changed:showing(0, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(1, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]

** (process:5499): WARNING **: Unable to open bus connection: Empty address ''

** (process:5499): WARNING **: Unable to open bus connection: Empty address ''
object:state-changed:showing(0, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(1, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [DEAD]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [image | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(1, 0, 0)
	source: [image | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(1, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]


* Below is the output when alt-tab is pressed. state-changed:selected shows up.

onKeyPressOrRelease: pressed
	hw_code: 64
	event_string: Alt_L
	modifiers: 0
	id: 65513
	timestamp: 10189757
	is_text: True
object:state-changed:showing(1, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(1, 0, 0)
	source: [panel | ]
	host_application: [application | gnome-shell]
object:state-changed:selected(1, 0, 0)
	source: [push button | ]
	host_application: [application | gnome-shell]
object:state-changed:selected(0, 0, 0)
	source: [push button | ]
	host_application: [application | gnome-shell]
object:state-changed:selected(1, 0, 0)
	source: [push button | ]
	host_application: [application | gnome-shell]
object:state-changed:selected(0, 0, 0)
	source: [push button | ]
	host_application: [application | gnome-shell]
object:state-changed:selected(1, 0, 0)
	source: [push button | ]
	host_application: [application | gnome-shell]
object:state-changed:selected(0, 0, 0)
	source: [push button | ]
	host_application: [application | gnome-shell]
object:state-changed:selected(1, 0, 0)
	source: [push button | ]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [DEAD]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [DEAD]
	host_application: [application | gnome-shell]
object:state-changed:showing(0, 0, 0)
	source: [DEAD]
	host_application: [application | gnome-shell]


