On Wed, Nov 29, 2017 at 7:18 PM, Mario Corchero <mariocj89@gmail.com> wrote:
There were discussions about having it a function, making the constructor of datetime accept a string(this was strongly rejected), having a static function in datetime, etc... and there was no real agreement.

Guido has written several times that a named constructor is the way forward.  The name "fromisoformat" was more or less agreed upon as well.  In fact, Mathieu Dupuy's patch was 95% there.