Fixed #3165 -- Really allow underscores when making a superuser, thanks `SmileyChris`.

import getpass

import os

import sys

import re

RE_VALID_USERNAME = re.compile('\w+$')

def createsuperuser(username=None, email=None, password=None):

    """

                username = raw_input(input_msg + ': ')

            if default_username and username == '':

                username = default_username

            if not username.isalnum():

            if not RE_VALID_USERNAME.match(username):

                sys.stderr.write("Error: That username is invalid. Use only letters, digits and underscores.\n")

                username = None

                continue