code: def download(self, download_key, raise_exception_on_failure=False):
          
          query = {"output": "json", "user_credentials": self.api_key}
          resp = requests.get(
              "%sdownload/%s" % (self._url, download_key),
              params=query,
              timeout=self._timeout,
          )
  
          if raise_exception_on_failure and resp.status_code != 200:
              raise DocumentDownloadFailure(resp.content, resp.status_code)
          return resp
docs: Download the file represented by the download_key.