CAISO wind generation historical data

[jsnmedeiros]

Dear all,
I am trying to get wind generation data for CAISO, I am using the following commands

import pandas as pd
from pyiso import client_factory,LOGGER
from pyiso.base import BaseClient
from datetime import datetime, date, time
caiso=client_factory('CAISO')
start="01/2016"
end="08/2018"
date1=datetime.strptime(start,"%m/%Y")
date2=datetime.strptime(end,"%m/%Y")
data=caiso.get_generation(start_at=date1,end_at=date2,market='RTM',fuels='wind',tz_name='UTC')

I get the following error:
2016-03-13 02:00:00
Traceback (most recent call last):
File "", line 1, in
File "/home/SPEEDWELLUK/medeirosj/source/pyiso/pyiso-master/pyiso/caiso.py", line 88, in get_generation
return self._generation_historical()
File "/home/SPEEDWELLUK/medeirosj/source/pyiso/pyiso-master/pyiso/caiso.py", line 234, in _generation_historical
df = df[df.THERMAL.map(str) != '#VALUE!']
File "/usr/lib64/python2.7/site-packages/pandas/core/generic.py", line 2744, in getattr
return object.getattribute(self, name)
AttributeError: 'DataFrame' object has no attribute 'THERMAL'

I've only just installed pyiso and I am not sure if I am doing the right thing.
would really appreciate the help

many thanks
Joana