code: def test_3_2_3_2():
      """
      Make sure callbacks are never called more than once.
      """
  
      c = Counter()
      p1 = Promise.reject(Exception("Error"))
      p2 = p1.then(None, lambda v: c.tick())
      p2._wait()
      try:
          # I throw an exception
          p1.do_reject(Exception("Error"))
          assert False  # Should not get here!
      except AssertionError:
          # This is expected
          pass
      assert 1 == c.value()
  
imports: from promise import Promise
  from .utils import assert_exception
  from threading import Event
label_desc: Use image node_id 8 for calling a global function with example usage: test_3_2_3_2() without return types