code: def test_memory(self, input_param, expected_key_size):
      input_data = {}
      for i in range(50):
          input_data[str(i)] = [time.time()] * 100000
      result = SelectItemsd(**input_param)(input_data)
      self.assertEqual(len(result.keys()), expected_key_size)
      self.assertSetEqual(set(result.keys()), set(input_param["keys"]))
      self.assertGreaterEqual(
          sys.getsizeof(input_data)
          * float(expected_key_size)
          / len(input_data),
          sys.getsizeof(result),
      )
  
file_path: MONAI/tests/test_select_itemsd.py
imports: from __future__ import annotations
  import sys
  import time
  import unittest
  from parameterized import parameterized
  from monai.transforms import SelectItemsd
label_desc: Use image node_id 1 for calling the TestSelectItemsd obj's underlying member method code with example usage: obj.test_memory(input_param, expected_key_size) without return types