code: def test_get_reward(self, net_worths):
      portfolio = Portfolio(USD)
      portfolio._performance = net_worths_to_dict(net_worths)
  
      pct_chg = net_worths.pct_change()
  
      reward_scheme = rewards.SimpleProfit()
      assert (
          reward_scheme.get_reward(portfolio) == pct_chg.iloc[-1]
      )  # default window size 1
  
      reward_scheme._window_size = 3
      reward = (
          (1 + pct_chg.iloc[-1])
          * (1 + pct_chg.iloc[-2])
          * (1 + pct_chg.iloc[-3])
      ) - 1
      assert reward_scheme.get_reward(portfolio) == reward
  
file_path: tensortrade/tests/tensortrade/unit/env/default/test_rewards.py
imports: import pytest
  import numpy
  import pandas
  from collections import OrderedDict
  import tensortrade.env.default.rewards
  from tensortrade.core import TradingContext
  from tensortrade.oms.wallets import Portfolio
  from tensortrade.oms.instruments import USD
label_desc: Use image node_id 1 for calling the TestSimpleProfit obj's underlying member method code with example usage: obj.test_get_reward(net_worths) without return types