code: def test_drawdown(self):
      for period in PERIODS:
          self.assertTrue(
              all(x["max_drawdown"] == 0 for x in self.metrics[period])
          )
  
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 3 for calling the TestRisk obj's underlying member method code with example usage: obj.test_drawdown() without return types