Fatal error: Uncaught TypeError: Return value of Material::search_by_field() must be of the type array, bool returned in /home/kavec/www/kavec.ed.jp/public_html/materials/app/Material.php:163 Stack trace: #0 /home/kavec/www/kavec.ed.jp/public_html/materials/app/Material.php(106): Material->search_by_field(3, false) #1 /home/kavec/www/kavec.ed.jp/public_html/materials/search.php(15): Material->variety_search('\xEF\xBF\xBD\xEF\xBF\xBD\xEF\xBF\xBD\xEF\xBF\xBD\xEF\xBF\xBD...') #2 /home/kavec/www/kavec.ed.jp/public_html/materials/index.php(24): include_once('/home/kavec/www...') #3 {main} thrown in /home/kavec/www/kavec.ed.jp/public_html/materials/app/Material.php on line 163