diff --git a/src/Traits/ExcelExportable.php b/src/Traits/ExcelExportable.php
index acbd9d1..15c94be 100644
--- a/src/Traits/ExcelExportable.php
+++ b/src/Traits/ExcelExportable.php
@@ -333,7 +333,7 @@ protected function writeRow($sheet, $row, $rowIndex)
      *
      * @return mixed
      */
-    protected function getValue($row, $key)
+    protected function getValue($row, $key = null)
     {
         return self::dataGet($row, $key);
     }