Fatal error: Uncaught Error: Argument 1 passed to Booking_Form::is_visible() must be of the type int, null given, called in /home/xs348848/nagano-house.jp/public_html/wp-content/themes/nagano-house/templates/template-event-form.php on line 3
in /home/xs348848/nagano-house.jp/public_html/wp-content/themes/nagano-house/inc/class-booking-form.php on line 263

コールスタック:

1. Booking_Form::is_visible()
   wp-content/themes/nagano-house/templates/template-event-form.php:3
2. require()
   wp-includes/template.php:772
3. load_template()
   wp-includes/template.php:716
4. locate_template()
   wp-includes/general-template.php:204
5. get_template_part()
   wp-content/themes/nagano-house/templates/page-event-form.php:19
6. include()
   wp-includes/template-loader.php:106
7. require_once()
   wp-blog-header.php:19
8. require()
   index.php:17