code: def _get_payout_total(self, positions):
      payouts = []
      for asset, old_price in iteritems(self._payout_last_sale_prices):
          pos = positions[asset]
          amount = pos.amount
          payout = calc_payout(
              asset.multiplier, amount, old_price, pos.last_sale_price
          )
          payouts.append(payout)
  
      return sum(payouts)
  
imports: from __future__ import division
  import logbook
  import numpy
  from collections import namedtuple
  from catalyst.assets import Future
  from six import itervalues, iteritems
  import catalyst.protocol
  from catalyst.constants import LOG_LEVEL
label_desc: Use image node_id 14 for calling the PerformancePeriod obj's underlying member method code with example usage: obj._get_payout_total(positions) and returns: sum