Correct debug code

lib/helper.php

@@ -29,6 +29,10 @@ class Helper{
 		self::log($message, \OCP\Util::WARN);
 	}
 
+	public static  function errorLog($message){
+		self::log($message, \OCP\Util::ERROR);
+	}
+	
 	public static function log($message, $level){
 		\OCP\Util::writeLog(self::APP_ID, $message, $level);
 	}

lib/session.php

@@ -32,6 +32,7 @@ class Session extends Db{
 		if ($result){
 			return $data;
 		}
+		
 		return false;
 	}
 	
@@ -75,11 +76,13 @@ class Session extends Db{
 	public static function getSessionByFileId($fileId){
 		$sessions = self::getSessionsByFileIds(array($fileId));
 		if (count($sessions) > 1) {
-			return $sessions[0];
-		} else {
-			\OCP\Util::writeLog('documents','more than one session found for file id '.$fileId,\OCP\Util::ERROR);
+			Helper::errorLog('documents','more than one session found for file id ' . $fileId);
+		}
+		
+		if (count($sessions)) {
 			return $sessions[0];
 		}
+		
 		return null;
 	}