code: def _register_upload(self, authdata, reg_key):
          
          reg_headers = {
              "Content-Type": "application/x-www-form-urlencoded",
              "If-None-Match": "*",
          }
          reg_headers.update(self.zinstance.default_headers())
          reg_data = {"upload": authdata.get("uploadKey")}
          upload_reg = requests.post(
              url=self.zinstance.endpoint
              + "/{t}/{u}/items/{i}/file".format(
                  t=self.zinstance.library_type, u=self.zinstance.library_id, i=reg_key
              ),
              data=reg_data,
              headers=dict(reg_headers),
          )
          try:
              upload_reg.raise_for_status()
          except requests.exceptions.HTTPError:
              error_handler(upload_reg)
docs: Step 3: upload successful, so register it