docs: def raw_file(client, src, dest, opt):
      """Write the contents of a vault path/key to a file. Is
      smart enough to attempt and handle binary files that are
      base64 encoded."""
      path, key = path_pieces(src)
      resp = client.read(path)
      if not resp:
          client.revoke_self_token()
          raise aomi.exceptions.VaultData("Unable to retrieve %s" % path)
      else:
          if 'data' in resp and key in resp['data']:
              secret = resp['data'][key]
              if is_base64(secret):
                  LOG.debug('decoding base64 entry')
                  secret = portable_b64decode(secret)
  
              if is_aws(resp['data']) and 'sts' not in path:
                  renew_secret(client, resp, opt)
  
              write_raw_file(secret, dest)
          else:
              client.revoke_self_token()
              e_msg = "Key %s not found in %s" % (key, path)
              raise aomi.exceptions.VaultData(e_msg)