text: #
  # Copyright 2013 Quantopian, Inc.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  import pandas as pd
  import requests
  import os
  
  
  def get_benchmark_returns(symbol):
      """
      Get a Series of benchmark returns from IEX associated with `symbol`.
      Default is `SPY`.
  
      Parameters
      ----------
      symbol : str
          Benchmark symbol for which we're getting the returns.
  
      The data is provided by IEX (https://iextrading.com/), and we can
      get up to 5 years worth of data.
      """
      r = requests.get(
          #'https://api.iextrading.com/1.0/stock/{}/chart/5y'.format(symbol)
          'https://cloud.iexapis.com/stable/stock/{}/chart/5y?chartCloseOnly=True&token={}'
              .format(symbol, os.environ['IEXAPIS_TOKEN'])
      )
      data = r.json()
  
      df = pd.DataFrame(data)
  
      df.index = pd.DatetimeIndex(df['date'])
      df = df['close']
  
      return df.sort_index().tz_localize('UTC').pct_change(1).iloc[1:]
  