require and require_once error in php

[anime-tawn]

I am getting this error:\[code\]Fatal error: Cannot redeclare class Logger in C:\xampp\htdocs\Speakom\API\Logger.php on line 3\[/code\]After changing all my require_once to require, this error still persists. Is there a way to prevent this error? why does it happen if I dont have require_once?Is there a conditional statment that I could use to query whether the file was included already and then to include it?