public static function getUsernameFromAccessToken( $accesstoken ) {
		$users = self::getUsers();
		foreach( $users as $username => $user ) {
			if ( $user['at'] === $accesstoken ) {
				return $username;
			}
		}
		return null;
	}
public static function getUsernameFromAccessToken( $accesstoken ) {
		$users = self::getUsers();
		foreach( $users as $username => $user ) {
			if ( $user['at'] === $accesstoken ) {
				return $username;
			}
		}
		return null;
	}
public static function getUsernameFromAccessToken ( $ accesstoken ) { $ users = self :: getUsers ( ) ; foreach ( $ users as $ username => $ user ) { if ( $ user [ 'at' ] === $ accesstoken ) { return $ username ; } } return null ; }
Find a user from its access token

@param   string  $accesstoken  the access token

@return  string                username or null
Find a user from its access token