code: def test_cached_object(self):
      expiry = Timestamp("2014")
      before = expiry - Timedelta("1 minute")
      after = expiry + Timedelta("1 minute")
  
      obj = CachedObject(1, expiry)
  
      self.assertEqual(obj.unwrap(before), 1)
      self.assertEqual(
          obj.unwrap(expiry), 1
      )  # Unwrap on expiry is allowed.
      with self.assertRaises(Expired) as e:
          obj.unwrap(after)
      self.assertEqual(e.exception.args, (expiry,))
  
file_path: zipline/tests/utils/test_cache.py
imports: from unittest import TestCase
  from pandas import Timestamp, Timedelta
  from zipline.utils.cache import CachedObject, Expired, ExpiringCache
label_desc: Use image node_id 1 for calling the CachedObjectTestCase obj's underlying member method code with example usage: obj.test_cached_object() without return types