with open('test1', 'ab') as f:
    f.write('koko')
with open('test1', 'rb') as f:
    f.read()
with open('test1', 'wa') as f:
    f.write('coco')
with open('test1', 'rb') as f:
    f.read()
Write a list in a python csv file, one new row per list