def getHistoricData(symbols =  ['VIX','VXV','VXMT','VVIX']):
    if not isinstance(symbols,list):
        symbols = [symbols]
    
    urls = {'VIX':'http://www.cboe.com/publish/ScheduledTask/MktData/datahouse/vixcurrent.csv',
            'VXV':'http://www.cboe.com/publish/scheduledtask/mktdata/datahouse/vxvdailyprices.csv',
            'VXMT':'http://www.cboe.com/publish/ScheduledTask/MktData/datahouse/vxmtdailyprices.csv',
            'VVIX':'http://www.cboe.com/publish/scheduledtask/mktdata/datahouse/VVIXtimeseries.csv'}
    
    startLines = {'VIX':1,'VXV':2,'VXMT':2,'VVIX':1}
    cols = {'VIX':'VIX Close','VXV':'CLOSE','VXMT':'Close','VVIX':'VVIX'}
    
    data = {}
  
    for symbol in symbols:
        urlStr = urls[symbol]
        print 'Downloading %s from %s' % (symbol,urlStr)
        
        data[symbol] = pd.read_csv(urllib2.urlopen(urlStr), header=startLines[symbol],index_col=0,parse_dates=True)[cols[symbol]]
    
    
    return pd.DataFrame(data)
    
 

#---------------------classes--------------------------------------------
Sets the global TF session.
dataset/ETHPy150Open sjev/trading-with-python/lib/cboe.py/getHistoricData--crossover with--dataset/ETHPy150Open fchollet/keras/keras/backend/tensorflow_backend.py/set_session