code: def testForceTimeUnit(self):
      self.assertEqual(
          "40s",
          cli_shared.time_to_readable_str(
              40e6, force_time_unit=cli_shared.TIME_UNIT_S
          ),
      )
      self.assertEqual(
          "40000ms",
          cli_shared.time_to_readable_str(
              40e6, force_time_unit=cli_shared.TIME_UNIT_MS
          ),
      )
      self.assertEqual(
          "40000000us",
          cli_shared.time_to_readable_str(
              40e6, force_time_unit=cli_shared.TIME_UNIT_US
          ),
      )
      self.assertEqual(
          "4e-05s",
          cli_shared.time_to_readable_str(
              40, force_time_unit=cli_shared.TIME_UNIT_S
          ),
      )
      self.assertEqual(
          "0",
          cli_shared.time_to_readable_str(
              0, force_time_unit=cli_shared.TIME_UNIT_S
          ),
      )
  
      with self.assertRaisesRegex(ValueError, r"Invalid time unit: ks"):
          cli_shared.time_to_readable_str(100, force_time_unit="ks")
  
imports: from collections import namedtuple
  from tensorflow.python.debug.cli import cli_shared
  from tensorflow.python.debug.cli import debugger_cli_common
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import googletest
label_desc: Use image node_id 5 for calling the TimeToReadableStrTest obj's underlying member method code with example usage: obj.testForceTimeUnit() without return types