def _get_unprocessed_uri(swagger_spec, processed_uris):
    """
    Retrieve an un-process URI from swagger spec referred URIs

    :type swagger_spec: bravado_core.spec.Spec
    :param processed_uris: URIs of the already processed URIs

    :rtype: str
    """
    for uri in swagger_spec.resolver.store:
        if uri not in processed_uris:
            return uri
