diff --git a/src/Command/CommandInterface.php b/src/Command/CommandInterface.php
index 9f349e1d..8e0b57be 100644
--- a/src/Command/CommandInterface.php
+++ b/src/Command/CommandInterface.php
@@ -73,7 +73,7 @@ interface CommandInterface
     /**
      * Parses a raw response and returns a PHP object.
      *
-     * @param string $data Binary string containing the whole response.
+     * @param string|array|null $data Binary string containing the whole response.
      *
      * @return mixed
      */