code: def test_iops(self):
      try:
          iops = [isub, iand, ior, ixor]
      except NameError:
          return  # Don't exist in older Python versions.
      for op in iops:
          # Mutating operators, so make fresh copies.
          lazy = LazySet(self.base)
          base = self.base.copy()
          op(lazy, set([1]))
          op(base, set([1]))
          self.assertEqual(lazy, base, str(op))
  
imports: from operator import eq, ge, gt, le, lt, ne, add, concat, not_, sub, and_, or_, xor
  import os.path
  import sys
  import unittest
  import warnings
  from pytz.lazy import LazyList, LazySet
label_desc: Use image node_id 4 for calling the LazySetTestCase obj's underlying member method code with example usage: obj.test_iops() without return types