code: def test_security_add_delete(self):
      with security_list_copy():
  
          def get_datetime():
              return pd.Timestamp("2015-01-27", tz="UTC")
  
          rl = SecurityListSet(get_datetime, self.asset_finder)
          self.assertNotIn(
              "BZQ",
              rl.leveraged_etf_list.current_securities(get_datetime()),
          )
          self.assertNotIn(
              "URTY",
              rl.leveraged_etf_list.current_securities(get_datetime()),
          )
  
imports: from datetime import timedelta
  import pandas
  from nose_parameterized import parameterized
  from zipline.algorithm import TradingAlgorithm
  from zipline.errors import TradingControlViolation
  from zipline.testing import add_security_data, security_list_copy
  from zipline.testing.fixtures import WithMakeAlgo, ZiplineTestCase
  from zipline.utils import factory
  from zipline.utils.security_list import SecurityListSet, load_from_directory
label_desc: Use image node_id 4 for calling the SecurityListTestCase obj's underlying member method code with example usage: obj.test_security_add_delete() and returns: pd