def linkify_only_full_urls(attrs, new=False):
    """Linkify only full links, containing the scheme."""
    if not new:  # This is an existing <a> tag, leave it be.
        return attrs

    # If the original text doesn't contain the scheme, don't linkify.
    if not attrs['_text'].startswith(('http:', 'https:')):
        return None

    return attrs