'The output() member function outputs the rows of data at a
time to the output.txt file which is used as the k/v store
for the FatHead IA.'

def output(self, data_list):

    with open('output.txt', 'a') as f:
        for data in data_list:
            line = self.concat(data[0], data[2], data[3], data[1])
            f.write(line.encode('utf'))
