histPanel = web.DataReader(STOCKS_PREDICT, 'iex', startDate, endDate)

# Cleanse data: remove dates where there is NaN and 0
for item, df in histPanel.iteritems():
    for minor, ts in df.iteritems():
        for major, value in ts.iteritems():
            if float(value) == 0:
                histPanel[item][minor][major] = 'NaN'

histPanel = histPanel.dropna(axis=1, how='any')

return histPanel