python在dict里面使用datetime.now()不能正常显示

dtime = datetime.now()
print(dtime)
items = []
for i in range(len(df)):
    dict = {}
    dict['name'] = df.iloc[i][0]
    dict['type_id'] = 6
    dict['author'] = df.iloc[i][2]
    dict['content'] = df.iloc[i][3]
    dict['add_time'] = dtime.strftime("%Y-%m-%d %H:%M:%S.%f")
    dict['md5_id'] = a.computeMd5(df.iloc[i])
    items.append(dict)

需要使用strftime("%Y-%m-%d %H:%M:%S.%f")才能正常输出