class_docstr: Timer functions and utilities
code: def test_timer(self):
      with Timer() as timer:
          pass
      assert isinstance(timer.interval, float)
      assert timer.interval == pytest.approx(8.6)
  
imports: import pytest
  from unittest import mock
  from yellowbrick.utils.timer import *
label_desc: Use image node_id 1 for calling the TestTimer obj's underlying member method code with example usage: obj.test_timer() without return types