def _route53_op(body=None, **kw):
    """
    Construct an L{_Operation} representing a I{Route53} service API call.
    """
    op = _Operation(service=b"route53", **kw)
    if body is None:
        return succeed(op)
    d = to_xml(body)
    d.addCallback(lambda body: attr.assoc(op, body=body))
    return d