#!/usr/bin/env python3

import os
import sys
import email
import email.utils

try:
    input = sys.argv[1]
except:
    print('no input file', file = sys.stderr)
    sys.exit(1)

with open(input, 'rb') as f:
    msg = email.message_from_binary_file(f)
    val = msg.get('from')
    print('From: %s' % email.utils.getaddresses([val]))