Calling function question

1 
stage.addEventListener(Event.DEACTIVATE,callMenu);
...
function callMenu(e:Event)
        {
        //game is paused and a menu is brought up.
        }

if i also want to call the menu within another function which is not the same type of event, should i pass in null ?

example: a switch statement finds the correct keyboard input has been pressed, is it bad to use callMenu(null);…it seemed to work, but feels wrong.

thanks for the help.