code: def test_PiecewiseScheduler_with_empty(self):
      with self.assertRaises(AssertionError):
          scheduler = PiecewiseScheduler([])
  
file_path: PARL/parl/utils/tests/scheduler_test.py
imports: import unittest
  import numpy
  from parl.utils.scheduler import *
label_desc: Use image node_id 4 for calling the TestScheduler obj's underlying member method code with example usage: obj.test_PiecewiseScheduler_with_empty() without return types