How do I link a csv file to flask?

#Retrieve data from db (logs/log_db/sht.#.db ; # = run_id = SHT30_#.log, #)
def getData():
    conn = sqlite3.connect('logs/log_db/sht.%s.db' %run_id)
    cur = conn.cursor()
    for row in cur.execute('''SELECT Itn, Temp, Humi FROM READING'''):
        Itn = str(row[0])
        Temp = str(row[1])
        Humi = str(row[2])
    conn.close()
    return Itn, Temp, Humi
    
#main route
@app.route("/")
def index():
    Itn, Temp, Humi = getData()
    templateData = {
        'Itn': Itn,
        'Temp': Temp,
        'Humi': Humi
    }
    return(render_template('index.html', **templateData))