code: def setup(self, num_lines):
      # create the equivalent of a two-column CSV file
      # with date strings in the first column and random
      # floating point data in the second column
      dates = np.arange("today", 20, dtype=np.datetime64)
      np.random.seed(123)
      values = np.random.rand(20)
      date_line = ""
  
      for date, value in zip(dates, values):
          date_line += str(date) + "," + str(value) + "\n"
  
      # expand data to specified number of lines
      data = date_line * (num_lines // 20)
      self.csv_data = StringIO(data)
  
imports: from .common import Benchmark, get_squares, get_squares_
  import numpy
  from io import SEEK_SET, StringIO, BytesIO
label_desc: Use image node_id 1 for calling the LoadtxtCSVDateTime obj's underlying member method code with example usage: obj.setup(num_lines) without return types