code: def test_default_backend_name():
      pool = pa.default_memory_pool()
      assert pool.backend_name in possible_backends
  
imports: import contextlib
  import os
  import signal
  import subprocess
  import sys
  import weakref
  import pyarrow
  import pytest
label_desc: Use image node_id 8 for calling a global function with example usage: test_default_backend_name() without return types