code: def update_items(self, payload):
          
          to_send = [self.check_items([p])[0] for p in payload]
          headers = {}
          headers.update(self.default_headers())
          # the API only accepts 50 items at a time, so we have to split
          # anything longer
          for chunk in chunks(to_send, 50):
              req = requests.post(
                  url=self.endpoint
                  + "/{t}/{u}/items/".format(t=self.library_type, u=self.library_id),
                  headers=headers,
                  data=json.dumps(chunk),
              )
              self.request = req
              try:
                  req.raise_for_status()
              except requests.exceptions.HTTPError:
                  error_handler(req)
              return True
docs: Update existing items
          Accepts one argument, a list of dicts containing Item data