lib/packages/core-classes.js
function(event_name, fn, context, listener_args) {

		return this._addListener(event_name, fn, context, listener_args, this._listeners)

	}
function(event_name, fn, context, listener_args) {

		return this._addListener(event_name, fn, context, listener_args, this._listeners)

	}
function ( event_name , fn , context , listener_args ) { return this . _addListener ( event_name , fn , context , listener_args , this . _listeners ) }
Add listener for event `event_name`

@param {string} event_name Name of the event to listen to
@param {function} fn The callback
@param {Object} context The context for callback execution (an object, to which the callback belongs)
@param {*} [listener_args] Static listener arguments. May be usable when one callback responds to different events
@returns {_tListener} Listener structure, which later may be suspended, or removed via call to {@link Lava.mixin.Observable#removeListener}
Add listener for event event_name