human
Solve the following python programming problem given the following code:
@cronjobs.register
def send_welcome_emails():
assistant
#Here is the Python code you requested.

    """Send a welcome email to first time contributors.
    Anyone who has made a contribution more than 24 hours ago and has not
    already gotten a welcome email should get a welcome email.
    """
    wait_period = (datetime.now() - timedelta(hours=24))
    messages = []
    context = {'host': Site.objects.get_current().domain}
    answer_filter = Q(created__lte=wait_period)
    answer_filter &= (~ Q(question__creator=F('creator')))
    answer_filter &= Q(creator__profile__first_answer_email_sent=False)
    answer_recipient_ids = set(Answer.objects.filter(answer_filter).values_list('creator', flat=True))
    @safe_translation
    def _make_answer_email(locale, to):
        return make_mail(subject=_('Thank    you    for    your    contribution    to    Mozilla    Support!'), text_template='community/email/first_answer.ltxt', html_template='community/email/first_answer.html', context_vars=context, from_email=settings.TIDINGS_FROM_ADDRESS, to_email=to.email)
    for user in User.objects.filter(id__in=answer_recipient_ids):
        messages.append(_make_answer_email(user.profile.locale, user))
    l10n_filter = Q(created__lte=wait_period)
    l10n_filter &= (~ Q(document__locale=settings.WIKI_DEFAULT_LANGUAGE))
    l10n_filter &= Q(creator__profile__first_l10n_email_sent=False)
    l10n_recipient_ids = set(Revision.objects.filter(l10n_filter).values_list('creator', flat=True))
    for user in User.objects.filter(id__in=l10n_recipient_ids):
        messages.append(make_mail(subject='Thank    you    for    your    contribution    to    Mozilla    Support!', text_template='community/email/first_l10n.ltxt', html_template='community/email/first_l10n.html', context_vars=context, from_email=settings.TIDINGS_FROM_ADDRESS, to_email=user.email))
    send_messages(messages)
    Profile.objects.filter(user__id__in=answer_recipient_ids).update(first_answer_email_sent=True)
    Profile.objects.filter(user__id__in=l10n_recipient_ids).update(first_l10n_email_sent=True)