def METHOD_NAME(url, security_tenant):
    '''Appends the security_tenant query string parameter to the url'''
    parsed = urlsplit(url)
    if parsed.query:
        qs = parse_qsl(parsed.query, keep_blank_values=True, strict_parsing=True)
    else:
        qs = []
    qs.append(('security_tenant', security_tenant))
    new_query = urlencode(qs)
    new_args = parsed._replace(query=new_query)
    new_url = urlunsplit(new_args)
    return new_url