def METHOD_NAME(request, readout_slug, readouts, locale=None, mode=None, product=None):
    """Instantiate and return the readout with the given slug.
    Raise Http404 if there is no such readout.
    """
    if readout_slug not in readouts:
        raise Http404
    return readouts[readout_slug](request, locale=locale, mode=mode, product=product)