code: def test_pipe_flush(self):
      pipe = Pipe()
      pipe.flush()
  
file_path: horovod/test/single/test_util.py
imports: import unittest
  from horovod.runner.util.streams import Pipe
  from horovod.runner.util.threads import in_thread
label_desc: Use image node_id 9 for calling the UtilTests obj's underlying member method code with example usage: obj.test_pipe_flush() without return types