`start` received with timezone defined as 'UTC' although a Date must be timezone naive

Strategy Backtesting
#1

Hi, the following code get an error: Parameter start received with timezone defined as ‘UTC’ although a Date must be timezone naive.

if remove tz_localize(‘UTC’),then it works. I wonder why. and if it’s correct to remove tz_localize(‘UTC’)?

def initialize(context):
    pass

def handle_data(context, data):
    order(symbol('AAPL'), 10)
    # print('qtb=data ', symbol('AAPL'))
    
    record(AAPL=data.current(symbol('AAPL'), fields = ['price']))
    # record(AAPL=data[symbol('AAPL')].price)


start = pd.Timestamp('2014')
end = pd.Timestamp('2018')

# sp500 = web.DataReader('SP500', 'fred', start, end).SP500
# benchmark_returns = sp500.pct_change()

result = run_algorithm(start=start.tz_localize('UTC'),
                       end=end.tz_localize('UTC'),
                       initialize=initialize,
                       handle_data=handle_data,
                       capital_base=100000,
                    #    benchmark_returns=benchmark_returns,
                       bundle='quandl',
                       data_frequency='daily')
#2

I had the same issue and got it to work making the dates timezone naive. Your ‘result’ will actually be "UTC’ as shown here:
image