diff --git a/core/lib/Drupal/Core/Config/Schema/Sequence.php b/core/lib/Drupal/Core/Config/Schema/Sequence.php
index c47fd55..01312d2 100644
--- a/core/lib/Drupal/Core/Config/Schema/Sequence.php
+++ b/core/lib/Drupal/Core/Config/Schema/Sequence.php
@@ -24,13 +24,7 @@ class Sequence extends ArrayElement {
   protected function getElementDefinition($key) {
     $value = isset($this->value[$key]) ? $this->value[$key] : NULL;
     // @todo: Remove BC layer for sequence with hyphen in front. https://www.drupal.org/node/2444979
-    $definition = array();
-    if (isset($this->definition['sequence'][0])) {
-      $definition = $this->definition['sequence'][0];
-    }
-    elseif ($this->definition['sequence']) {
-      $definition = $this->definition['sequence'];
-    }
+    $definition = isset($this->definition['sequence'][0]) ? $this->definition['sequence'][0] : (isset($this->definition['sequence']) ? $this->definition['sequence'] : array());
     return $this->buildDataDefinition($definition, $value, $key);
   }