code: def add(self, data):
      data_bytes = data.encode("utf-8")
      start = len(self._data_bytes)
  
      self._offsets_bytes.extend(
          start.to_bytes(
              8,
              byteorder=SpecWriter.byteorder,
              signed=SpecWriter.signed,
          )
      )
      self._data_bytes.extend(data_bytes)
  
      self._n_elements += 1
  
imports: import logging
  from typing import Literal, Tuple
  from hailtop.utils import secret_alnum_string
label_desc: Use image node_id 4 for calling the SpecWriter obj's underlying member method code with example usage: obj.add(data) without return types