class_docstr: Model commissions as free.
  
  Notes
  -----
  This is primarily used for testing.
class_docstr_tok: ["Model","commissions","as","free",".","Notes","--","--","-","This","is","primarily","used","for","testing","."]
code: def calculate(order, transaction):
      return 0.0
  
imports: from abc import abstractmethod
  from collections import defaultdict
  from six import with_metaclass
  from toolz import merge
  from zipline.assets import Equity, Future
  from zipline.finance.constants import FUTURE_EXCHANGE_FEES_BY_SYMBOL
  from zipline.finance.shared import AllowedAssetMarker, FinancialModelMeta
  from zipline.utils.dummy import DummyMapping
label_desc: Use image node_id 1 for calling the NoCommission obj's underlying member method code with example usage: obj.calculate(order, transaction) and returns: int