Python脚本无法执行游标插入语句

Question

不知道为什么我的代码无法执行游标insert语句。该代码运行良好，没有任何错误显示。.这是我的代码，有人可以帮忙吗？

for ticker in tickers:
    try:
        url = 'https://query1.finance.yahoo.com/v10/finance/quoteSummary/' + str(ticker) + '?formatted=true&crumb=kck%2FMrVs%2FSI&lang=en-GB&region=GB&modules=summaryProfile%2CfinancialData%2CrecommendationTrend%2CupgradeDowngradeHistory%2Cearnings%2CdefaultKeyStatistics%2CcalendarEvents%2CesgScores%2Cdetails&corsDomain=uk.finance.yahoo.com'
        print(url)
        response = requests.get(url)
        result = response.json()
        results = result['quoteSummary']['result']
        # print(results)
        if results == None:
            print('EMPTY')
        else:
            recom = results[0].get('upgradeDowngradeHistory')
            # print(recom['history'])
            for i in recom['history']:
                print(i)
                firm = i.get('firm')
                to_grade = i.get('toGrade')
                epoch_date = i.get('epochGradeDate')
                from_grade = i.get('fromGrade')
                print(firm, from_grade, to_grade, epoch_date)
                created_at= datetime.now
                cursor.execute("""insert into stocktwits_bank_recom(created_at,firm,from_grade,to_grade) VALUES ('%s','%s','%s','%s') ON CONFLICT ON CONSTRAINT unique_ratings DO NOTHING""",(created_at,firm,from_grade,to_grade))
                conn.commit()
    except:
        continue