:param manager: Context manager to handle transactions
    :type manager: Neo4jDBSessionManager
    :param relationship_id: Internal Neo4j relationship id
    :type relationship_id: int
    :return: Relationship model
    :rtype: models.BaseRelationshipModel

def get_relationship_model(manager, relationship_id):
    """
    :param manager: Context manager to handle transactions
    :type manager: Neo4jDBSessionManager
    :param relationship_id: Internal Neo4j relationship id
    :type relationship_id: int
    :return: Relationship model
    :rtype: models.BaseRelationshipModel
    """
    bundle = get_relationship_bundle(manager, relationship_id)
    return models.BaseRelationshipModel(manager).load(bundle)