contains all relevant notification settings.
The apply rule is applied on all host objects where the `host.address` is defined.
-If the host object as a specific custom attributed set, its value is inherited
+If the host object has a specific custom attribute set, its value is inherited
into the local notification object scope, e.g. `host.vars.notification_interval`,
`host.vars.notification_period` and `host.vars.notification_type`.
This overwrites attributes already specified in the imported `mail-host-notification`