chore: regens API reference docs (#889)

diff --git a/docs/dyn/youtube_v3.liveChatMessages.html b/docs/dyn/youtube_v3.liveChatMessages.html
index 4fef17a..f45bedd 100644
--- a/docs/dyn/youtube_v3.liveChatMessages.html
+++ b/docs/dyn/youtube_v3.liveChatMessages.html
@@ -78,7 +78,7 @@
   <code><a href="#delete">delete(id)</a></code></p>
 <p class="firstline">Deletes a chat message.</p>
 <p class="toc_element">
-  <code><a href="#insert">insert(part, body)</a></code></p>
+  <code><a href="#insert">insert(part, body=None)</a></code></p>
 <p class="firstline">Adds a message to a live chat.</p>
 <p class="toc_element">
   <code><a href="#list">list(liveChatId, part, profileImageSize=None, hl=None, maxResults=None, pageToken=None)</a></code></p>
@@ -97,12 +97,12 @@
 </div>
 
 <div class="method">
-    <code class="details" id="insert">insert(part, body)</code>
+    <code class="details" id="insert">insert(part, body=None)</code>
   <pre>Adds a message to a live chat.
 
 Args:
   part: string, The part parameter serves two purposes. It identifies the properties that the write operation will set as well as the properties that the API response will include. Set the parameter value to snippet. (required)
-  body: object, The request body. (required)
+  body: object, The request body.
     The object takes the form of:
 
 { # A liveChatMessage resource represents a chat message in a YouTube Live Chat.