code: def test_release_unused():
      pool = pa.default_memory_pool()
      pool.release_unused()
  
imports: import contextlib
  import os
  import signal
  import subprocess
  import sys
  import weakref
  import pyarrow
  import pytest
label_desc: Use image node_id 9 for calling a global function with example usage: test_release_unused() without return types