TypeError：需要浮点数PYTHON

Question

我目前的python脚本：

import ftplib
import hashlib
import httplib
import pytz
from datetime import datetime
import urllib
from pytz import timezone
import os.path, time
import glob

def ftphttp():
 dataset_path='Desktop'   
 files = glob.glob(dataset_path+"/images/*.png")   
 ts = files.sort(key=os.path.getmtime)
 dt = datetime.fromtimestamp(ts, pytz.utc)
 timeZone= timezone('Asia/Singapore')
 localtime = dt.astimezone(timeZone).isoformat()

 cam = "002"

 lscam = localtime + cam
 ftp = ftplib.FTP('localhost','kevin403','S$ip1234')
 ftp.cwd('/var/www/html/image')

 m=hashlib.md5()
 m.update(lscam)
 dd=m.hexdigest()

 for image in glob.glob(os.path.join('Desktop/images/*.png')):
  with open(image, 'rb') as file:
    ftp.storbinary('STOR '+dd+ '.png', file)

 x = httplib.HTTPConnection('localhost', 8086)
 x.connect()
 f = {'ts' : localtime}
 x.request('GET','/camera/store?cam='+cam+'&'+urllib.urlencode(f)+'&fn='+dd)
 y = x.getresponse()
 z=y.read()
 x.close()
 ftp.quit()

引用：

Traceback (most recent call last):
File "<pyshell#49>", line 1, in <module>
 ftphttp()
File "/home/kevin403/Testtimeloop.py", line 17, in ftphttp
 dt = datetime.fromtimestamp(ts, pytz.utc)
TypeError: a float is required

我尝试获取文件夹中的文件列表以获取其修改后的时间戳并将其存储在数据库中。但我似乎无法做到这一点。有人知道怎么做吗？我已经尝试了很长时间，而且我是蟒蛇新手。