:param manager: Manager to handle sessions and transactions
    :param relationship_id: Unique id
    :param legacy: Backwards compatibility

    :type manager: norduniclient.contextmanager.Neo4jDBSessionManager
    :type relationship_id: int
    :type legacy: Boolean

    :rtype int|neo4j.v1.types.Relationship

def get_relationship(manager, relationship_id, legacy=True):
    """
    :param manager: Manager to handle sessions and transactions
    :param relationship_id: Unique id
    :param legacy: Backwards compatibility

    :type manager: norduniclient.contextmanager.Neo4jDBSessionManager
    :type relationship_id: int
    :type legacy: Boolean

    :rtype int|neo4j.v1.types.Relationship
    """
    q = """
        MATCH ()-[r]->()
        WHERE ID(r) = {relationship_id}
        RETURN r
        """
    with manager.session as s:
        record = s.run(q, {'relationship_id': int(relationship_id)}).single()
        if record:
            if legacy:
                return record['r'].properties
            return record['r']
    raise exceptions.RelationshipNotFound(manager, int(relationship_id))