code: def create_url(self):
          
          headers = self.headers
          headers['upload-length'] = str(self.file_size)
          headers['upload-metadata'] = ','.join(self.encode_metadata())
          resp = requests.post(self.client.url, headers=headers)
          url = resp.headers.get("location")
          if url is None:
              msg = 'Attempt to retrieve create file url with status {}'.format(resp.status_code)
              raise TusCommunicationError(msg, resp.status_code, resp.content)
          return urljoin(self.client.url, url)
docs: Return upload url.
  
          Makes request to tus server to create a new upload url for the required file upload.