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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def switch_region(request, region_name, redirect_field_name=auth.REDIRECT_FIELD_NAME):
 """Switches the user's region for all services except Identity service. The region will be switched if the given region is one of the regions available for the scoped project. Otherwise the region is not switched. """

    if region_name in request.user.available_services_regions:
        request.session['services_region'] = region_name
        LOG.debug('Switching services region to %s for user "%s".',
                  region_name, request.user.username)

    redirect_to = request.GET.get(redirect_field_name, '')
    if not is_safe_url(url=redirect_to, host=request.get_host()):
        redirect_to = settings.LOGIN_REDIRECT_URL

    response = shortcuts.redirect(redirect_to)
    utils.set_response_cookie(response, 'services_region',
                              request.session['services_region'])
    return response