add annotations for thrown exceptions

src/Provider/Node/FallbackNodeProvider.php

@@ -43,6 +43,7 @@ class FallbackNodeProvider implements NodeProviderInterface
      * and returning the first non-empty value found
      *
      * @return string System node ID as a hexadecimal string
+     * @throws \Exception
      */
     public function getNode()
     {

src/Provider/Node/RandomNodeProvider.php

@@ -28,6 +28,7 @@ class RandomNodeProvider implements NodeProviderInterface
      * Returns the system node ID
      *
      * @return string System node ID as a hexadecimal string
+     * @throws \Exception if it was not possible to gather sufficient entropy
      */
     public function getNode()
     {