use DateTimeInterface

Author: JanTvrdik

src/Application/UI/Presenter.php

@@ -748,7 +748,7 @@ public function canonicalize()
 
 	/**
 	 * Attempts to cache the sent entity by its last modification date.
-	 * @param  string|int|\DateTime  last modified time
+	 * @param  string|int|\DateTimeInterface  last modified time
 	 * @param  string strong entity tag validator
 	 * @param  mixed  optional expiration time
 	 * @return void