WordPress: Set Sorting for Admin Column on a CPT

functions.php

add_filter( 'request', 'we_complete_column_orderby' );
/**
* Sorting for the 'Complete' column in Submissions (we_submission) CPT, browse admin page
* 
*/
function we_complete_column_orderby( $vars ) {
	if ( isset( $vars['orderby'] ) && 'we_item-complete' == $vars['orderby'] ) {
		$vars = array_merge( $vars, array(
		'meta_key' => 'we_item-complete',
		'orderby' => 'meta_value'
		) );
	}

	return $vars;
}