gistfile1.py

import random
import re

simple_word_regex = re.compile('^[a-z]+$')

word_list = []
with open('/usr/share/dict/american-english', 'r') as words_file:
    for word_line in words_file:
        word = word_line.strip()
        if simple_word_regex.match(word):
            word_list.append(word)
            
def generate_password(length=4):
    return ' '.join(
        word_list[random.randint(0, len(word_list))]
        for _ in xrange(length)
    )