I am afraid the remedy is not working

(1) had tried to add self in the parameter list, as cs.retrievelog(self)
the result being:
NameError: name 'self' is not defined

(2) For definition of method in class (as in def retrieveLog(self):), I think 'self' cannot be left out

Any suggestion?

I want to call a function inside strategy object to output a list member in the object, but it fail with
TypeError: retrieveLog() missing 1 required positional argument: 'self'
Please enlighten me on how to do it properly?

from __future__ import (absolute_import, division, print_function,
                        unicode_literals)


# Create a Stratey
class simpleStrategy(bt.Strategy):

    def log(self, txt, dt=None):
        ''' Logging function for this strategy'''
        dt = dt or self.datas[0].datetime.date(0)
        logLine = '%s, %s' % (dt.isoformat(), txt)
        
        # LOG TO LIST INSTEAD OF PRINTING IT OUT
        self.logStr.append(logLine)


    def __init__(self):
        # Keep a reference to the "close" line in the data[0] dataseries
        self.dataclose = self.datas[0].close

        # To keep track of log string
        self.logStr = []

    def next(self):
        # log to list
        self.log('test')
        
    # PRINT THE LOG LIST
    def retrieveLog(self):
        print(self.logStr)
        
 

 

cerebro = bt.Cerebro()

# Add a strategy
cs = simpleStrategy
cerebro.addstrategy(cs)

# Add the Data Feed to Cerebro1
cerebro.adddata(bt.feeds.PandasData(dataname=theDf))


# Print out the starting conditions
print('Starting Portfolio Value: %.2f' % cerebro.broker.getvalue())

# Run over everything
cerebro.run()

# Print out the final result
print('Final Portfolio Value: %.2f' % cerebro.broker.getvalue())


#  -------------- ERROR ---------------------------------
# TypeError: retrieveLog() missing 1 required positional argument: 'self'
cs.retrieveLog()