No puede seleccionar más de 25 temasLos temas deben comenzar con una letra o número, pueden incluir guiones ('-') y pueden tener hasta 35 caracteres de largo.
We recently had someone in the support room who set it to `false`
and the playbook ran without any issues.
This currently seems to yield the same result as 'none', but it's
better to avoid such behavior.
Slavi Pantaleev