code: def test_line_numbers(self):
      output = StringIO()
      writer = csv_py3.Writer(output, line_numbers=True)
      writer.writerow(["a", "b", "c"])
      writer.writerow(["1", "2", "3"])
      writer.writerow(["4", "5", "ʤ"])
  
      written = StringIO(output.getvalue())
  
      reader = csv_py3.Reader(written)
      self.assertEqual(next(reader), ["line_number", "a", "b", "c"])
      self.assertEqual(next(reader), ["1", "1", "2", "3"])
      self.assertEqual(next(reader), ["2", "4", "5", "ʤ"])
  
imports: import csv
  import os
  import platform
  import sys
  import unittest
  from io import StringIO
  from agate import csv_py3
  from agate.exceptions import FieldSizeLimitError
label_desc: Use image node_id 3 for calling the TestWriter obj's underlying member method code with example usage: obj.test_line_numbers() without return types