anchor.diff:  
       ExistingAccount = case read_keys(KeysDir) of
           {ok, _, _} -> true;
  -        _ -> false;
  +        _ -> false
       end,
   
       try
           case ExistingAccount of
  +            true ->
                   ?info("Let's Encrypt: reusing account from \"~s\"", [filename:absname(KeysDir)]);
  -            error ->
  +            false ->
                   ?info("Let's Encrypt: generating new Let's Encrypt account keys"),
                   ok = generate_keys(KeysDir)
           end,
  
positive.code: -define(LE_POLL_INTERVAL, timer:seconds(3)).
  % Number of polls about authorization status
  -define(LE_POLL_ATTEMPTS, 10).
  % Number of failed request retries
  -define(GET_RETRIES, 3).
  -define(POST_RETRIES, 4).
  
negative.code:             ?info("No staging ACME server URL defined. Skipping staging run and running in production mode."),
              production;
          {full, _} ->
              ?info("Let's Encrypt: Starting test run against staging server before actual "
              "Let's Encrypt certification"),
              full;
          {_, undefined} -> throw("No staging ACME server URL defined. Cannot perform test run"),
              throw({error, no_letsencrypt_staging_server});
  