def logout_allowed(service):
    """Check if a given service identifier should be sent a logout request."""
    if hasattr(settings, 'MAMA_CAS_SERVICES'):
        return _is_allowed('logout_allowed', service)

    if hasattr(settings, 'MAMA_CAS_ENABLE_SINGLE_SIGN_OUT'):
        warnings.warn(
            'The MAMA_CAS_ENABLE_SINGLE_SIGN_OUT setting is deprecated. SLO '
            'should be configured using MAMA_CAS_SERVICES.', DeprecationWarning)
    return getattr(settings, 'MAMA_CAS_ENABLE_SINGLE_SIGN_OUT', False)