def get_iteration(conn, config, **kwargs):
    """Get data from every interation of each method for each instance

    Parameter:
        - conn (object): mysql connection
        - config (dict): configuration of experiment
        - kwargs:
            + method_id
            + instance_id
    """
    cur = conn.cursor()
    values = []
    for key in kwargs:
        values.append('%s=%d' % (key, kwargs[key]))
    query = 'SELECT * FROM iteration WHERE %s ' % ' AND '.join(values)
    cur.execute(query)
    for _ in cur.fetchall():
        yield _
