'Return a sample.
:param sample_id: the id of the sample.'

@wsme_pecan.wsexpose(Sample, wtypes.text)
def get_one(self, sample_id):

    rbac.enforce('get_sample', pecan.request)
    f = storage.SampleFilter(message_id=sample_id)
    samples = list(pecan.request.storage_conn.get_samples(f))
    if (len(samples) < 1):
        raise base.EntityNotFound(_('Sample'), sample_id)
    return Sample.from_db_model(samples[0])
