code: def list_objects(self, instance, bucket_name, prefix=None, delimiter=None):
          
          url = '/buckets/{}/{}'.format(instance, bucket_name)
          params = {}
          if prefix is not None:
              params['prefix'] = prefix
          if delimiter is not None:
              params['delimiter'] = delimiter
          response = self._client.get_proto(path=url, params=params)
          message = rest_pb2.ListObjectsResponse()
          message.ParseFromString(response.content)
          return ObjectListing(message, instance, bucket_name, self)
docs: List the objects for a bucket.
  
          :param str instance: A Yamcs instance name.
          :param str bucket_name: The name of the bucket.
          :param str prefix: If specified, only objects that start with this
                             prefix are listed.
          :param str delimiter: If specified, return only objects whose name
                                do not contain the delimiter after the prefix.
                                For the other objects, the response contains
                                (in the prefix response parameter) the name
                                truncated after the delimiter. Duplicates are
                                omitted.