code: def download_url(url, filename, headers):
      
      ensure_dirs(filename)
      response = requests.get(url, headers=headers, stream=True)
      if response.status_code == 200:
          with open(filename, 'wb') as f:
              for chunk in response.iter_content(16 * 1024):
                  f.write(chunk)
docs: Download a file from `url` to `filename`.