diff --git a/index.html b/index.html
index ac42cb1..0af84f4 100644
--- a/index.html
+++ b/index.html
@@ -209,7 +209,7 @@ <h2>
           undefined removeRange(Range range);
           undefined removeAllRanges();
           undefined empty();
-          sequence&lt;StaticRange&gt; getComposedRanges(ShadowRoot... shadowRoots);
+          sequence&lt;StaticRange&gt; getComposedRanges(optional GetComposedRangesOptions options = {});
           undefined collapse(Node? node, optional unsigned long offset = 0);
           undefined setPosition(Node? node, optional unsigned long offset = 0);
           undefined collapseToStart();
@@ -222,6 +222,10 @@ <h2>
           boolean containsNode(Node node, optional boolean allowPartialContainment = false);
           stringifier;
         };
+
+        dictionary GetComposedRangesOptions {
+          sequence<ShadowRoot> shadowRoots = [];
+        };
       </pre>
       <dl>
         <dt>