dct = {"A": [100, 200, 300]}
connection = pymysql.connect(host='localhost',
                             user='root',
                             password='',                             
                             db='test',
                             cursorclass=pymysql.cursors.DictCursor)
cursor=connection.cursor()
sql = "INSERT INTO slovari VALUES (NULL,%s)"
cursor.execute(sql, json.dumps(dct))
connection.commit()