class_docstr: Accumulates CSV lines in case of multiline strings.
code: def _read_internal(self) -> str:
      if not self._accumulator:
          return ""
      if len(self._accumulator) == 1:
          return self._accumulator[0]
      return "".join(self._accumulator)
  
imports: import os
  from typing import Any, Dict, Iterable, List
  from absl import logging
  import apache_beam
  import tensorflow
  from tfx.components.example_gen.base_example_gen_executor import BaseExampleGenExecutor
  from tfx.dsl.io import fileio
  from tfx.types import standard_component_specs
  from tfx.utils import io_utils
  from tfx_bsl.coders import csv_decoder
label_desc: Use image node_id 3 for calling the _CsvLineBuffer obj's underlying member method code with example usage: obj._read_internal() and returns: str, str, self