Filter events listing page by category globally

/*
 Filter default events listing page by events category globally
 Where 3 is the events category id
 */
function my_em_default_category( $defaults ){

	if ( is_array($defaults['category']) && !empty($defaults['category']) ){
		array_push( $defaults['category'], 3 );
	}
	else if ( !is_array($defaults['category']) && !empty($defaults['category']) ){
		$defaults['category'] .= ",3";
	}
	else{
		$defaults['category'] = 3;
	}

    return $defaults;
}
add_filter('em_events_get_default_search','my_em_default_category',100,1);