#!/usr/bin/env python

# write 4000000 lines in csv.csv file
with open('csv.csv', 'w') as f:
    for i in xrange(0, 4000000):
        f.write('aaa, bbb,ccc , ddd,eee,fff,ggg,hhh,iii,jjj,kkk,lll,mmm,nnn\n')