Docserver: there is only one.

chrome/common/extensions/docs/server2/rietveld_patcher.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import json
 import tarfile
 from StringIO import StringIO
 
 from file_system import FileNotFoundError, ToUnicode
 from future import Future
@@ skipping 156 matching lines @@
 
   def Apply(self, paths, file_system, binary, version=None):
     if version is None:
       version = self.GetVersion()
     return Future(delegate=_AsyncFetchFuture(self._base_path,
                                              self._issue,
                                              version,
                                              paths,
                                              binary,
                                              self._fetcher))
+
+  def GetIdentity(self):
+    return self._issue