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('\xE5\x86\x99\xE7\x9C\x9F\xE6\xA9\x9F\xE3\x83\xBB\xE3\x83\x87...') #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