if STREAM.isatty():

[Rhodri James]

On 29/08/2019 14:37, Hongyi Zhao wrote:
> On Thu, 29 Aug 2019 13:23:07 +0100, Rhodri James wrote:
> 
>> TLDR: these two lines set up (but don't output) a progress message for
>> an interactive stream.
> Thanks a lot for your deeply notes on this.  But, if so, when will the
> ``else ...'' be executed in the original code:

When the stream isn't connected to an interactive terminal, obviously. 
For example, when it's writing to file.

-- 
Rhodri James *-* Kynesim Ltd