code: def test_main_with_time_unit(self):
      unit_sec = self.run_main(
          seconds_per_increment=0.003, switches=["-u", "sec"]
      )
      self.assertEqual(
          unit_sec, "100 loops, best of 5: 0.003 sec per loop\n"
      )
      unit_msec = self.run_main(
          seconds_per_increment=0.003, switches=["-u", "msec"]
      )
      self.assertEqual(
          unit_msec, "100 loops, best of 5: 3 msec per loop\n"
      )
      unit_usec = self.run_main(
          seconds_per_increment=0.003, switches=["-u", "usec"]
      )
      self.assertEqual(
          unit_usec, "100 loops, best of 5: 3e+03 usec per loop\n"
      )
      # Test invalid unit input
      with captured_stderr() as error_stringio:
          invalid = self.run_main(
              seconds_per_increment=0.003, switches=["-u", "parsec"]
          )
      self.assertEqual(
          error_stringio.getvalue(),
          "Unrecognized unit. Please select nsec, usec, msec, or sec.\n",
      )
  
imports: import timeit
  import unittest
  import sys
  import io
  from textwrap import dedent
  from test.support import captured_stdout
  from test.support import captured_stderr
label_desc: Use image node_id 43 for calling the TestTimeit obj's underlying member method code with example usage: obj.test_main_with_time_unit() without return types