code: def _save_chunk(self, start_i, end_i):
      data_index = self.data_index
  
      # create the data for a chunk
      slicer = slice(start_i, end_i)
      for i in range(len(self.blocks)):
          b = self.blocks[i]
          d = b.to_native_types(
              slicer=slicer,
              na_rep=self.na_rep,
              float_format=self.float_format,
              decimal=self.decimal,
              date_format=self.date_format,
              quoting=self.quoting,
          )
  
          for col_loc, col in zip(b.mgr_locs, d):
              # self.data is a preallocated list
              self.data[col_loc] = col
  
      ix = data_index.to_native_types(
          slicer=slicer,
          na_rep=self.na_rep,
          float_format=self.float_format,
          decimal=self.decimal,
          date_format=self.date_format,
          quoting=self.quoting,
      )
  
      libwriters.write_csv_rows(
          self.data, ix, self.nlevels, self.cols, self.writer
      )
  
file_path: catboost/contrib/python/pandas/py2/pandas/io/formats/csvs.py
imports: from __future__ import print_function
  import csv
  import os
  import warnings
  from zipfile import ZipFile
  import numpy
  from pandas._libs import writers
  from pandas.compat import StringIO, range, zip
  from pandas.core.dtypes.generic import ABCDatetimeIndex, ABCIndexClass, ABCMultiIndex, ABCPeriodIndex
  from pandas.core.dtypes.missing import notna
  from pandas import compat
  from pandas.io.common import UnicodeWriter, _get_handle, _infer_compression, get_filepath_or_buffer
label_desc: Use image node_id 5 for calling the CSVFormatter obj's underlying member method code with example usage: obj._save_chunk(start_i, end_i) without return types