code: def test_impossible_dependency(self):
      self.minimum_engines(2)
      view = self.client.load_balanced_view()
      ar1 = view.apply_async(lambda: 1)
      ar1.get()
      e1 = ar1.engine_id
      e2 = e1
      while e2 == e1:
          ar2 = view.apply_async(lambda: 1)
          ar2.get()
          e2 = ar2.engine_id
  
      with view.temp_flags(follow=[ar1, ar2]):
          with raises_remote(error.ImpossibleDependency):
              view.apply_sync(lambda: 1)
  
imports: import time
  from itertools import count
  import pytest
  import ipyparallel
  from ipyparallel import error
  from .clienttest import ClusterTestCase, crash, raises_remote
label_desc: Use image node_id 18 for calling the TestLoadBalancedView obj's underlying member method code with example usage: obj.test_impossible_dependency() without return types