code: def testDoesntCrashWhenFileIsDeleted(self):
      self._WriteToFile("a", "a")
      self._LoadAllEvents()
      os.remove(os.path.join(self._directory, "a"))
      self._WriteToFile("b", "b")
      self.assertWatcherYields(["b"])
  
imports: import os
  import shutil
  import tensorflow
  from tensorboard.backend.event_processing import directory_watcher
  from tensorboard.backend.event_processing import io_wrapper
label_desc: Use image node_id 18 for calling the DirectoryWatcherTest obj's underlying member method code with example usage: obj.testDoesntCrashWhenFileIsDeleted() without return types