Removed unused and redefined imports.

from django.contrib.auth import REDIRECT_FIELD_NAME

from django.contrib.auth.decorators import login_required

from django.contrib.auth.forms import AuthenticationForm

from django.contrib.auth.forms import PasswordResetForm, SetPasswordForm, PasswordChangeForm, AdminPasswordChangeForm

from django.contrib.auth.forms import PasswordResetForm, SetPasswordForm, PasswordChangeForm

from django.contrib.auth.tokens import default_token_generator

from django.core.exceptions import PermissionDenied

from django.core.urlresolvers import reverse

from django.shortcuts import render_to_response, get_object_or_404

from django.contrib.sites.models import Site, RequestSite

from django.http import HttpResponseRedirect, Http404

from django.template import RequestContext

from django.utils.http import urlquote, base36_to_int

from django.utils.html import escape

from django.utils.translation import ugettext as _

from django.contrib.auth.models import User

from django.views.decorators.cache import never_cache

import re

def login(request, template_name='registration/login.html', redirect_field_name=REDIRECT_FIELD_NAME):

    "Displays the login form and handles the login action."

        if form.is_valid():

            # Light security check -- make sure redirect_to isn't garbage.

            if not redirect_to or '//' in redirect_to or ' ' in redirect_to:

                from django.conf import settings

                redirect_to = settings.LOGIN_REDIRECT_URL

            from django.contrib.auth import login

            login(request, form.get_user())

def logout_then_login(request, login_url=None):

    "Logs out the user if he is logged in. Then redirects to the log-in page."

    if not login_url:

        from django.conf import settings

        login_url = settings.LOGIN_URL

    return logout(request, login_url)

def redirect_to_login(next, login_url=None, redirect_field_name=REDIRECT_FIELD_NAME):

    "Redirects the user to the login page, passing the given 'next' page"

    if not login_url:

        from django.conf import settings

        login_url = settings.LOGIN_URL

    return HttpResponseRedirect('%s?%s=%s' % (login_url, urlquote(redirect_field_name), urlquote(next)))