docs: def options(self, request, *args, **kwargs):
          """
          Implements a OPTIONS HTTP method function returning all allowed HTTP
          methods.
          """
          allow = []
          for method in self.http_method_names:
              if hasattr(self, method):
                  allow.append(method.upper())
          r = self.render_to_response(None)
          r['Allow'] = ','.join(allow)
          return r