code: def test_size_limit_constraint(tmpdir):
      """Testing trivial NullCache: should trigger value generating function on each run"""
      # We will write total of 5MB to the cache (50KB items x 100)
      RECORD_SIZE_BYTES = 50 * KB
      RECORDS_COUNT = 100
  
      a_record = np.random.randint(
          0, 255, (RECORD_SIZE_BYTES,), np.uint8
      )
      cache = LocalDiskCache(
          tmpdir.strpath, 1 * MB, RECORD_SIZE_BYTES, shards=1
      )
  
      for i in range(RECORDS_COUNT):
          cache.get("some_key_{}".format(i), lambda: a_record)
  
      # Check that we are more or less within the size limit
      assert _recursive_folder_size(tmpdir.strpath) < 3 * MB
  
imports: import os
  import numpy
  from petastorm.local_disk_cache import LocalDiskCache
label_desc: Use image node_id 3 for calling a global function with example usage: test_size_limit_constraint(tmpdir) without return types