code: function ( arg ) {
  		var id;
  
  		if ( arg === global ) {
  			id = "window";
  		}
  		else if ( !server && arg === document ) {
  			id = "document";
  		}
  		else if ( !server && arg === document.body ) {
  			id = "body";
  		}
  		else {
  			utility.genId( arg );
  			id = arg.id || ( typeof arg.toString === "function" ? arg.toString() : arg );
  		}
  
  		return id;
  	}
docs: Gets the Observer id of arg
  
  @method id
  @param  {Mixed}  Object or String
  @return {String} Observer id