code: def leveraged_etf_list(self):
      if self._leveraged_etf is None:
          self._leveraged_etf = self.security_list_type(
              load_from_directory("leveraged_etf_list"),
              self.current_date_func,
              asset_finder=self.asset_finder,
          )
      return self._leveraged_etf
  
imports: import warnings
  from datetime import datetime
  from os import listdir
  import os.path
  import pandas
  import pytz
  import catalyst
  from catalyst.errors import SymbolNotFound
  from catalyst.finance.asset_restrictions import SecurityListRestrictions
  from catalyst.catalyst_warnings import ZiplineDeprecationWarning
label_desc: Use image node_id 2 for calling the SecurityListSet obj's underlying member method code with example usage: obj.leveraged_etf_list() and returns: self