chore: regens API reference docs (#889)

diff --git a/docs/dyn/books_v1.cloudloading.html b/docs/dyn/books_v1.cloudloading.html
index 7ab41fb..2b045d9 100644
--- a/docs/dyn/books_v1.cloudloading.html
+++ b/docs/dyn/books_v1.cloudloading.html
@@ -81,7 +81,7 @@
   <code><a href="#deleteBook">deleteBook(volumeId)</a></code></p>
 <p class="firstline">Remove the book and its contents</p>
 <p class="toc_element">
-  <code><a href="#updateBook">updateBook(body)</a></code></p>
+  <code><a href="#updateBook">updateBook(body=None)</a></code></p>
 <p class="firstline"></p>
 <h3>Method Details</h3>
 <div class="method">
@@ -115,11 +115,11 @@
 </div>
 
 <div class="method">
-    <code class="details" id="updateBook">updateBook(body)</code>
+    <code class="details" id="updateBook">updateBook(body=None)</code>
   <pre>
 
 Args:
-  body: object, The request body. (required)
+  body: object, The request body.
     The object takes the form of:
 
 {