$prefix = '_yourprefix_';
	$cmb_demo = new_cmb2_box( array(
 		'id'           => $prefix . 'metabox',
 		'title'        => __( 'Test Metabox', 'cmb2' ),
 		'object_types' => array( 'post', ), // Post type
 		'context'      => 'normal',
 		'priority'     => 'high',
 		'show_names'   => true,
 
 	) );
 
 	$cmb_demo->add_field( array(
 		'name'       => __( 'Test Date Range', 'cmb2' ),
 		'desc'       => __( 'field description (optional)', 'cmb2' ),
 		'id'         => $prefix . 'date_range',
 		'type'       => 'date_range',
 	) );