code: def _retrieve_data(self, request=None):
          
          full_url = "%s%s" % (self.endpoint, request)
          # The API doesn't return this any more, so we have to cheat
          self.self_link = request
          self.request = requests.get(url=full_url, headers=self.default_headers())
          self.request.encoding = "utf-8"
          try:
              self.request.raise_for_status()
          except requests.exceptions.HTTPError:
              error_handler(self.request)
          return self.request
docs: Retrieve Zotero items via the API
          Combine endpoint and request to access the specific resource
          Returns a JSON document