code: def post_multipart(host, selector, fields, files):
      
      content_type, body = encode_multipart_formdata(fields, files)
      h = httplib.HTTP(host)
      h.putrequest('POST', selector)
      h.putheader('content-type', content_type)
      h.putheader('content-length', str(len(body)))
      h.endheaders()
      h.send(body)
      errcode, errmsg, headers = h.getreply()
      return h.file.read()
docs: Post fields and files to an http host as multipart/form-data.
      fields is a sequence of (name, value) elements for regular form fields.
      files is a sequence of (name, filename, value) elements for data to be uploaded as files
      Return the server's response page.