code: def test_show_multigpu(self):
      times = numpy.array([[5.4], [6.4], [7.0], [8.1]]) * 1e-6
      perf = cupyx.time._PerfCaseResult(
          "test_name_xxx", times, (0, 1, 2)
      )
      assert str(perf) == (
          "test_name_xxx       :    CPU:     5.400 us "
          "    GPU-0:     6.400 us "
          "    GPU-1:     7.000 us "
          "    GPU-2:     8.100 us"
      )
  
file_path: cupy/tests/cupyx_tests/test_time.py
imports: import unittest
  from unittest import mock
  import numpy
  import cupy
  from cupy import testing
  import cupyx
label_desc: Use image node_id 5 for calling the TestPerfCaseResult obj's underlying member method code with example usage: obj.test_show_multigpu() without return types