old_contents: import pandas as pd
  import matplotlib.pyplot as plt
  import numpy as np
  import pandas.io.data as web
  
  plt.ion()
  
  instruments = pd.read_csv('instruments2.csv')
  
  startdate = '2005-01-28'
  enddate = '2014-11-10'
  
  # Download the asset data if the data isn't there,
  # or it doesn't match the instruments in the csv file.
  try:
      baseetfs = pd.read_csv('data/base_price_data.csv')
  except IOError:
      baseetfs = web.DataReader(instruments.values.flatten().tolist(), 'google', startdate, enddate)
      baseetfs = baseetfs.Close
      baseetfs.to_csv('data/base_price_data.csv')
  
new_contents: import pandas as pd
  import matplotlib.pyplot as plt
  import numpy as np
  import pandas.io.data as web
  
  plt.ion()
  
  instruments = pd.read_csv('instruments2.csv')
  
  startdate = '2005-01-28'
  enddate = '2014-11-10'
  
  # Download the asset data if the data isn't there,
  # or it doesn't match the instruments in the csv file.
  try:
      baseetfs = pd.read_csv('data/base_price_data.csv')
  except IOError:
      baseetfs = web.DataReader(instruments.values.flatten().tolist(), 'google', startdate, enddate)
      baseetfs = baseetfs.Close.convert_objects(convert_numeric=True)
      baseetfs.to_csv('data/base_price_data.csv')
      
subject: set numeric conversion