pygtk3 checking does signal exist

Question

how can I learn this before connecting anything.

example

does_signal_exist(widget, signal):
    pass

button = Gtk.Button()

does_signal_exist(button, "clicked") # returns True
does_signal_exist(button, "hello") # returns False
does_signal_exist(button, "unboxed") # returns False
does_signal_exist(button, "button-press-event") # returns True

Answer 1

def does_signal_exist(gtkWidgetObj, sigTag):
    try:
        gtkWidgetObj.emit(sigTag)
        return True
    except:
        return "unknown signal name" not in format_exc():