title: Upload Image using POST form data in Python-requests
body: <p>I'm working with wechat APIs ...
  here I've to upload an image to wechat's server using this API
  <a href="http://admin.wechat.com/wiki/index.php?title=Transferring_Multimedia_Files" rel="noreferrer">http://admin.wechat.com/wiki/index.php?title=Transferring_Multimedia_Files</a></p>
  <pre class="lang-py prettyprint-override"><code>url = 'http://file.api.wechat.com/cgi-bin/media/upload?access_token=%s&amp;type=image'%access_token
  files = {
      'file': (filename, open(filepath, 'rb')),
      'Content-Type': 'image/jpeg',
      'Content-Length': l
  }
  r = requests.post(url, files=files)
  </code></pre>
  <p>I'm not able to post data</p>