mboxext is a Mbox mailbox message extractor.
$ python mboxext.py -v /home/vagrant/Sent.mbox /home/vagrant/output/
2015-10-01 17:54:46,060 [mboxext] INFO - Target directory already exists and it's not empty
2015-10-01 17:54:46,061 [mboxext] INFO - Opening Mbox mailbox: /home/vagrant/Sent.mbox