code: def summary(dataset_uri, format):
      
      dataset = dtoolcore.DataSet.from_uri(dataset_uri)
      creator_username = dataset._admin_metadata["creator_username"]
      frozen_at = dataset._admin_metadata["frozen_at"]
      num_items = len(dataset.identifiers)
      tot_size = sum([dataset.item_properties(i)["size_in_bytes"]
                      for i in dataset.identifiers])
  
      if format == "json":
          json_lines = [
              '{',
              '  "name": "{}",'.format(dataset.name),
              '  "uuid": "{}",'.format(dataset.uuid),
              '  "creator_username": "{}",'.format(creator_username),
              '  "number_of_items": {},'.format(num_items),
              '  "size_in_bytes": {},'.format(tot_size),
              '  "frozen_at": {}'.format(frozen_at),
              '}',
          ]
          formatted_json = "\n".join(json_lines)
          colorful_json = pygments.highlight(
              formatted_json,
              pygments.lexers.JsonLexer(),
              pygments.formatters.TerminalFormatter())
          click.secho(colorful_json, nl=False)
  
      else:
          info = [
              ("name", dataset.name),
              ("uuid", dataset.uuid),
              ("creator_username", creator_username),
              ("number_of_items", str(num_items)),
              ("size", sizeof_fmt(tot_size).strip()),
              ("frozen_at", date_fmt(frozen_at)),
          ]
          for key, value in info:
              click.secho("{}: ".format(key), nl=False)
              click.secho(value, fg="green")
docs: Report summary information about a dataset.