import csv
with open("test.csv","w",encoding='utf8') as csvfile:
  writer=csv.writer(csvfile)
  writer.writerow(["index","a_name","b_name"])
  writer.writerows([[0,'a1','b1'],[1,'a2','b2'],[2,'a3','b3']])

import csv
with open("test.csv","w",encoding='utf8',newline='') as csvfile:
  writer=csv.writer(csvfile)
  writer.writerow(["index","a_name","b_name"])
  writer.writerows([[0,'a1','b1'],[1,'a2','b2'],[2,'a3','b3']])

import csv
with open("test.csv","r") as csvfile:
  reader=csv.reader(csvfile)
  for line in reader:
    print(line)