code: def set_avatar(self, avatar, subject_descriptor):
          
          route_values = {}
          if subject_descriptor is not None:
              route_values['subjectDescriptor'] = self._serialize.url('subject_descriptor', subject_descriptor, 'str')
          content = self._serialize.body(avatar, 'Avatar')
          self._send(http_method='PUT',
                     location_id='801eaf9c-0585-4be8-9cdb-b0efa074de91',
                     version='5.1-preview.1',
                     route_values=route_values,
                     content=content)
docs: SetAvatar.
          [Preview API]
          :param :class:`<Avatar> <azure.devops.v5_1.graph.models.Avatar>` avatar:
          :param str subject_descriptor: