code: def test_threads(self):
      file_contents1 = "1" * (65536 + 1)
      file_contents2 = "2" * (65536 + 1)
  
      def call_multiple_puts_and_gets(cache):
          for _ in range(50):
              cache.put("foo", file_contents1.encode("utf-8").strip())
              cache.put("foo", file_contents2.encode("utf-8").strip())
              cache.get("foo")
              self.assertEqual(
                  cache.get("foo"),
                  file_contents2.encode("utf-8").strip(),
              )
  
      with tempfile.TemporaryDirectory() as tmpdir:
          cache = GFileCache(tmpdir)
          threads = []
          for _ in range(50):
              t = threading.Thread(
                  target=call_multiple_puts_and_gets(cache)
              )
              t.start()
              threads.append(t)
          for t in threads:
              t.join()
  
          self.assertEqual(
              cache.get("foo"), file_contents2.encode("utf-8").strip()
          )
  
file_path: jax/tests/gfile_cache_test.py
imports: import tempfile
  import threading
  from absl.testing import absltest
  from jax._src.gfile_cache import GFileCache
  import jax._src.test_util
label_desc: Use image node_id 7 for calling the FileSystemCacheTest obj's underlying member method code with example usage: obj.test_threads() without return types