code: function(property_name, fn, context, listener_args) {
  
  		return this._addListener(property_name, fn, context, listener_args, this._property_listeners);
  
  	}
docs: The same, as {@link Lava.mixin.Observable#on}, but returns listener to `property_name` instead of `event_name`
  
  @param {string} property_name Name of the property to listen for changes
  @param {function} fn The callback
  @param {Object} context The context for callback execution (an object, to which the callback belongs)
  @param {*} [listener_args] May be usable when one callback responds to changes of different properties
  @returns {_tListener} Listener construct, which may be removed or suspended later