def get_shorts(n_con, span, price_date):
    """
    INPUTS:
        n_con (mysql) - A "normal" pymysql database connection
        span (str) - 'daily' or 'weekly'
        price_date (str) - Data in ISO 8601 standard as YYYY-MM-DD
    OUTPUT:
        Returns a list of potential short candidates.
    """
    sql = ["SELECT symbol_id FROM {}_metrics".format(span),
           "WHERE price_date='{}'".format(price_date),
           "AND impulse<0",                                # negative impulse
           "AND gt26>0"]                                   # above value zone
    with n_con.cursor() as n_cur:
        n_cur.execute(" ".join(sql))
        results = n_cur.fetchall()

    return [result[0] for result in results]