docs: docs update (#911)

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Fixes #<issue_number_goes_here> 🦕
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+<style>
+
+body, h1, h2, h3, div, span, p, pre, a {
+  margin: 0;
+  padding: 0;
+  border: 0;
+  font-weight: inherit;
+  font-style: inherit;
+  font-size: 100%;
+  font-family: inherit;
+  vertical-align: baseline;
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+body {
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+  padding: 1em;
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+h1 {
+  font-size: 26px;
+  margin-bottom: 1em;
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+h2 {
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+  margin-bottom: 1em;
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+h3 {
+  font-size: 20px;
+  margin-bottom: 1em;
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+pre, code {
+  line-height: 1.5;
+  font-family: Monaco, 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', 'Lucida Console', monospace;
+}
+
+pre {
+  margin-top: 0.5em;
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+  font-family: Arial, sans serif;
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+h1, h2, h3 {
+  border-bottom: solid #CCC 1px;
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+
+.toc_element {
+  margin-top: 0.5em;
+}
+
+.firstline {
+  margin-left: 2 em;
+}
+
+.method  {
+  margin-top: 1em;
+  border: solid 1px #CCC;
+  padding: 1em;
+  background: #EEE;
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+.details {
+  font-weight: bold;
+  font-size: 14px;
+}
+
+</style>
+
+<h1><a href="displayvideo_v1.html">Display & Video 360 API</a> . <a href="displayvideo_v1.advertisers.html">advertisers</a> . <a href="displayvideo_v1.advertisers.channels.html">channels</a></h1>
+<h2>Instance Methods</h2>
+<p class="toc_element">
+  <code><a href="#get">get(advertiserId, channelId, partnerId=None, x__xgafv=None)</a></code></p>
+<p class="firstline">Gets a channel for a partner or advertiser.</p>
+<p class="toc_element">
+  <code><a href="#list">list(advertiserId, orderBy=None, partnerId=None, filter=None, pageToken=None, pageSize=None, x__xgafv=None)</a></code></p>
+<p class="firstline">Lists channels for a partner or advertiser.</p>
+<p class="toc_element">
+  <code><a href="#list_next">list_next(previous_request, previous_response)</a></code></p>
+<p class="firstline">Retrieves the next page of results.</p>
+<h3>Method Details</h3>
+<div class="method">
+    <code class="details" id="get">get(advertiserId, channelId, partnerId=None, x__xgafv=None)</code>
+  <pre>Gets a channel for a partner or advertiser.
+
+Args:
+  advertiserId: string, The ID of the advertiser that owns the fetched channel. (required)
+  channelId: string, Required. The ID of the channel to fetch. (required)
+  partnerId: string, The ID of the partner that owns the fetched channel.
+  x__xgafv: string, V1 error format.
+    Allowed values
+      1 - v1 error format
+      2 - v2 error format
+
+Returns:
+  An object of the form:
+
+    { # A single channel. Channels are custom groups of related websites and apps.
+    &quot;advertiserId&quot;: &quot;A String&quot;, # The ID of the advertiser that owns the channel.
+    &quot;name&quot;: &quot;A String&quot;, # Output only. The resource name of the channel.
+    &quot;displayName&quot;: &quot;A String&quot;, # Required. The display name of the channel.
+        # Must be UTF-8 encoded with a maximum length of 240 bytes.
+    &quot;partnerId&quot;: &quot;A String&quot;, # The ID of the partner that owns the channel.
+    &quot;channelId&quot;: &quot;A String&quot;, # Output only. The unique ID of the channel. Assigned by the system.
+  }</pre>
+</div>
+
+<div class="method">
+    <code class="details" id="list">list(advertiserId, orderBy=None, partnerId=None, filter=None, pageToken=None, pageSize=None, x__xgafv=None)</code>
+  <pre>Lists channels for a partner or advertiser.
+
+Args:
+  advertiserId: string, The ID of the advertiser that owns the channels. (required)
+  orderBy: string, Field by which to sort the list.
+Acceptable values are:
+
+* `displayName` (default)
+* `channelId`
+
+The default sorting order is ascending. To specify descending order for a
+field, a suffix &quot; desc&quot; should be added to the field name. Example:
+`displayName desc`.
+  partnerId: string, The ID of the partner that owns the channels.
+  filter: string, Allows filtering by channel fields.
+
+Supported syntax:
+
+* Filter expressions for channel currently can only contain at most one
+* restriction.
+* A restriction has the form of `{field} {operator} {value}`.
+* The operator must be `CONTAINS (:)`.
+* Supported fields:
+    - `displayName`
+
+Examples:
+
+* All channels for which the display name contains &quot;google&quot;:
+`displayName : &quot;google&quot;`.
+
+The length of this field should be no more than 500 characters.
+  pageToken: string, A token identifying a page of results the server should return.
+Typically, this is the value of
+next_page_token returned from the
+previous call to `ListChannels` method. If not specified, the first page
+of results will be returned.
+  pageSize: integer, Requested page size. Must be between `1` and `100`. If unspecified will
+default to `100`. Returns error code `INVALID_ARGUMENT` if an invalid value
+is specified.
+  x__xgafv: string, V1 error format.
+    Allowed values
+      1 - v1 error format
+      2 - v2 error format
+
+Returns:
+  An object of the form:
+
+    {
+    &quot;nextPageToken&quot;: &quot;A String&quot;, # A token to retrieve the next page of results.
+        # Pass this value in the page_token field
+        # in the subsequent call to `ListChannels` method to retrieve the next page
+        # of results.
+    &quot;channels&quot;: [ # The list of channels.
+        #
+        # This list will be absent if empty.
+      { # A single channel. Channels are custom groups of related websites and apps.
+        &quot;advertiserId&quot;: &quot;A String&quot;, # The ID of the advertiser that owns the channel.
+        &quot;name&quot;: &quot;A String&quot;, # Output only. The resource name of the channel.
+        &quot;displayName&quot;: &quot;A String&quot;, # Required. The display name of the channel.
+            # Must be UTF-8 encoded with a maximum length of 240 bytes.
+        &quot;partnerId&quot;: &quot;A String&quot;, # The ID of the partner that owns the channel.
+        &quot;channelId&quot;: &quot;A String&quot;, # Output only. The unique ID of the channel. Assigned by the system.
+      },
+    ],
+  }</pre>
+</div>
+
+<div class="method">
+    <code class="details" id="list_next">list_next(previous_request, previous_response)</code>
+  <pre>Retrieves the next page of results.
+
+Args:
+  previous_request: The request for the previous page. (required)
+  previous_response: The response from the request for the previous page. (required)
+
+Returns:
+  A request object that you can call &#x27;execute()&#x27; on to request the next
+  page. Returns None if there are no more items in the collection.
+    </pre>
+</div>
+
+</body></html>
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