diff --git a/src/Codeception/Specify/ResultPrinter.php b/src/Codeception/Specify/ResultPrinter.php
index 81ccdb1..b3c3d59 100644
--- a/src/Codeception/Specify/ResultPrinter.php
+++ b/src/Codeception/Specify/ResultPrinter.php
@@ -7,7 +7,7 @@ class ResultPrinter extends \PHPUnit\TextUI\ResultPrinter
     /**
      * @param string $progress
      */
-    protected function writeProgress($progress) : void
+    protected function writeProgress(string $progress) : void
     {
         $this->write($progress);
         $this->column++;
@@ -21,4 +21,4 @@ protected function writeProgress($progress) : void
     }
 
 
-}
\ No newline at end of file
+}