code: def set_slippage(self, us_equities=None, us_futures=None):
          
          if self.initialized:
              raise SetSlippagePostInit()
  
          if us_equities is not None:
              if Equity not in us_equities.allowed_asset_types:
                  raise IncompatibleSlippageModel(
                      asset_type='equities',
                      given_model=us_equities,
                      supported_asset_types=us_equities.allowed_asset_types,
                  )
              self.blotter.slippage_models[Equity] = us_equities
  
          if us_futures is not None:
              if Future not in us_futures.allowed_asset_types:
                  raise IncompatibleSlippageModel(
                      asset_type='futures',
                      given_model=us_futures,
                      supported_asset_types=us_futures.allowed_asset_types,
                  )
              self.blotter.slippage_models[Future] = us_futures
docs: Set the slippage models for the simulation.
  
          Parameters
          ----------
          us_equities : EquitySlippageModel
              The slippage model to use for trading US equities.
          us_futures : FutureSlippageModel
              The slippage model to use for trading US futures.
  
          See Also
          --------
          :class:`zipline.finance.slippage.SlippageModel`