<?php
// Edit admin columns
function my_page_columns($columns) {
	$columns = array(
		'cb'	 	=> '<input type="checkbox" />',
		'title' 	=> 'Title',
    'publish'	=>	'Publish date',
		'expire' 	=> 'Expire date',
		'date'		=>	'Date',
	);
	return $columns;
}

function my_custom_columns($column) {
	global $post;
	if($column == 'publish') {

    if(get_field('publish_date')) {
			echo get_field('publish_date');
		}

	} elseif($column == 'expire') {

		if(get_field('expire_date')) {
			echo get_field('expire_date');
		}

	}
}
function my_column_register_sortable( $columns )
{
	$columns['publish'] = 'publish';
	$columns['expire'] = 'expire';
	return $columns;
}

add_filter('manage_edit-webinar_sortable_columns', __NAMESPACE__ . '\\my_column_register_sortable' );
add_action('manage_webinar_posts_custom_column', __NAMESPACE__ . '\\my_custom_columns');
add_filter('manage_webinar_posts_columns', __NAMESPACE__ . '\\my_page_columns');