Access gmail and process emails from python

gmail.py

#!/usr/bin/python
#
# https://yuji.wordpress.com/2011/06/22/python-imaplib-imap-example-with-gmail
#
# To access gmail emails you must setup two factor authentication and then
# create an application specific password to the email bypassing the
# two factor authentication.

import imaplib
import email
import sys


def list_mail_folders():
    for i in mail.list()[1]:
        print i

def process_email(emails, em, matchstr):
    if matchstr in em:
        tokens = em.replace('>', '<').split('<')
        if len(tokens) > 0:
            line = ''
            for i in tokens:
                line += i.strip()
            emails[line] = emails.get(line, 0)
            emails[line] += 1

def process_list_of_emails(emails, field, matchstr):
    for i in field.split(','):
        if matchstr in i:
            process_email(emails, i, matchstr)

emails = {}
username = sys.argv[1]
password = sys.argv[2]
matchstr = sys.argv[3]

mail = imaplib.IMAP4_SSL('imap.gmail.com')
mail.login(username, password)
list_mail_folders()
mail.select("[Gmail]/All Mail")
#mail.select("inbox")
result, data = mail.search(None, "ALL")

id_list = data[0].split() # ids is a space separated string
print id_list
for i in id_list:
    result, data = mail.fetch(i, "(RFC822)")
    raw_email = data[0][1]
    e = email.message_from_string(raw_email)
    to = e.get('To', None)
    frm = e.get('From', None)
    cc = e.get('Cc', None)
    if frm and matchstr in frm:
        process_list_of_emails(emails, frm, matchstr)
    if cc and matchstr in cc:
        process_list_of_emails(emails, cc, matchstr)
    if to and matchstr in to:
        process_list_of_emails(emails, to, matchstr)

for i in emails.keys():
    print i