code: def files(self, payload):
          
          url = "{url_base}/resource/{pid}/files/".format(url_base=self.hs.url_base,
                                                         pid=self.pid)
  
          encoder = MultipartEncoder({
              "file": (payload['file'], open(payload['file'], 'r')),
              "folder": payload['folder']
          })
          monitor = MultipartEncoderMonitor(encoder, default_progress_callback)
  
          r = self.hs._request('POST', url, None, data=monitor, headers={'Content-Type': monitor.content_type})
          return r.text
docs: Upload a file to a hydroshare resource.
  
          :param payload:
              file: File object to upload to server
              folder: folder path to upload the file to
          :return: json object
              resource_id: string resource id,
              file_name: string name of file