class_docstr: A slippage model where all orders fill immediately and completely at the
  current close price.
  
  Notes
  -----
  This is primarily used for testing.
code: def process_order(data, order):
      return (
          data.current(order.asset, "close"),
          order.amount,
      )
  
imports: from __future__ import division
  from abc import abstractmethod
  import math
  import numpy
  from pandas import isnull
  from six import with_metaclass
  from toolz import merge
  from zipline.assets import Equity, Future
  from zipline.errors import HistoryWindowStartsBeforeData
  from zipline.finance.constants import ROOT_SYMBOL_TO_ETA
  from zipline.finance.shared import AllowedAssetMarker, FinancialModelMeta
  from zipline.finance.transaction import create_transaction
  from zipline.utils.cache import ExpiringCache
  from zipline.utils.dummy import DummyMapping
  from zipline.utils.input_validation import expect_bounded, expect_strictly_bounded
label_desc: Use image node_id 1 for calling the NoSlippage obj's underlying member method code with example usage: obj.process_order(data, order) and returns: data,  order