Read file, CSV read String

import os, csv, sys
import argparse
import StringIO
import csv

parser = argparse.ArgumentParser(description='parse csv file')
parser.add_argument('-f', '--file', required=True)

args = parser.parse_args()
file = args.file

i = 1
tmp = ''
f = open(file,'r')  
for line in f:     
	i = i + 1
	if line.startswith('['):
		line = line[1:-2] 				
		f = StringIO.StringIO(line)
		reader = csv.reader(f, delimiter=',')
		for row in reader:
			if row[0] == tmp:
				print row[3];
			else :
				print line,
				tmp = row[0]
	#if i > 500 :
	#	break
f.close()