diff --git a/app/common/Define/Money/Provider.php b/app/common/Define/Money/Provider.php
index 7680407..9a28da0 100644
--- a/app/common/Define/Money/Provider.php
+++ b/app/common/Define/Money/Provider.php
@@ -8,9 +8,9 @@ interface Provider
 {
     /**
      * @param string $money_symbol
-     * @param DateTimeInterface $dateTime
+     * @param ?DateTimeInterface $dateTime = null
      * @return float
      * @throws EmptyResponse
      */
-    public function get(string $money_symbol, DateTimeInterface $dateTime): float;
+    public function get(string $money_symbol, ?DateTimeInterface $dateTime = null): float;
 }