code: def update(self, scaling_group, name=None, cooldown=None, min_entities=None,
              max_entities=None, metadata=None):
          
          return self._manager.update(scaling_group, name=name, cooldown=cooldown,
                  min_entities=min_entities, max_entities=max_entities,
                  metadata=metadata)
docs: Updates an existing ScalingGroup. One or more of the attributes can be
          specified.
  
          NOTE: if you specify metadata, it will *replace* any existing metadata.
          If you want to add to it, you either need to pass the complete dict of
          metadata, or call the update_metadata() method.