code: def test_trading_days(self):
      self.assertEqual(
          [x["trading_days"] for x in self.metrics["twelve_month"]],
          [251],
      )
      self.assertEqual(
          [x["trading_days"] for x in self.metrics["one_month"]],
          [20, 19, 23, 19, 22, 22, 20, 23, 20, 22, 21, 20],
      )
  
imports: import datetime
  import pandas
  import numpy
  from zipline.utils import factory
  from zipline.finance.trading import SimulationParameters
  import zipline.testing.fixtures
  from zipline.finance.metrics import _ClassicRiskMetrics
label_desc: Use image node_id 5 for calling the TestRisk obj's underlying member method code with example usage: obj.test_trading_days() without return types