code: def _test_index_mismatch_exception(self):
      # An exception is raised when returns and benchmark returns
      # have indexes that do not match
      bench_params = SimulationParameters(
          start_session=pd.Timestamp("2006-02-01", tz="UTC"),
          end_session=pd.Timestamp("2006-02-28", tz="UTC"),
          trading_calendar=self.trading_calendar,
      )
      benchmark = factory.create_returns_from_list(
          [BENCHMARK_BASE] * 19, bench_params
      )
      with np.testing.assert_raises(Exception):
          RiskMetricsPeriod(
              start_session=self.start_session,
              end_session=self.end_session,
              returns=self.algo_returns,
              benchmark_returns=benchmark,
              trading_calendar=self.trading_calendar,
              treasury_curves=self.env.treasury_curves,
          )
  
imports: import datetime
  import calendar
  import pandas
  import numpy
  import catalyst.finance.risk
  from catalyst.utils import factory
  from catalyst.finance.trading import SimulationParameters
  from catalyst.testing.fixtures import WithTradingEnvironment, CatalystTestCase
  from catalyst.finance.risk.period import RiskMetricsPeriod
label_desc: Use image node_id 24 for calling the TestRisk obj's underlying member method code with example usage: obj._test_index_mismatch_exception() without return types