code: def test_to_csv_nrows(self, nrows):
      df = DataFrame(
          np.ones((nrows, 4)),
          index=date_range("2020-01-01", periods=nrows),
          columns=Index(list("abcd"), dtype=object),
      )
      result, expected = self._return_result_expected(
          df, 1000, "dt", "s"
      )
      tm.assert_frame_equal(result, expected, check_names=False)
  
imports: import csv
  from io import StringIO
  import os
  import numpy
  import pytest
  from pandas.errors import ParserError
  import pandas
  from pandas import DataFrame, Index, MultiIndex, NaT, Series, Timestamp, date_range, period_range, read_csv, to_datetime
  import pandas._testing
  import pandas.core.common
  from pandas.io.common import get_handle
label_desc: Use image node_id 11 for calling the TestDataFrameToCSV obj's underlying member method code with example usage: obj.test_to_csv_nrows(nrows) without return types