def _set_location(instance, location):
    """Sets a ``Location`` response header. If the location does not start with
    a slash, the path of the current request is prepended.

    :param instance: Resource instance (used to access the request and
                     response)
    :type instance: :class:`webob.resource.Resource`
    """
    location = str(location)
    if not location.startswith('/'):
        location = urljoin(instance.request_path.rstrip('/') + '/', location)
    instance.response.location = location
Sets a ``Location`` response header. If the location does not start with
    a slash, the path of the current request is prepended.

    :param instance: Resource instance (used to access the request and
                     response)
    :type instance: :class:`webob.resource.Resource`