code: def test_invalid_unit(self):
      with self.assertRaises(ValueError):
          training.triggers.IntervalTrigger(1, "day")
  
file_path: chainer/tests/chainer_tests/training_tests/triggers_tests/test_interval_trigger.py
imports: from __future__ import division
  import random
  import tempfile
  import unittest
  import numpy
  from chainer import serializers
  from chainer import testing
  from chainer.testing import condition
  from chainer import training
label_desc: Use image node_id 1 for calling the TestInvalidIntervalTrigger obj's underlying member method code with example usage: obj.test_invalid_unit() without return types