Child emits an event, how the parent should catch it while the children are in the slot?

[grzegorztomasiak]

Parent
    <slot></slot>
    this.$on('someevent', () => {});  // of course there's no $on.
    
 Child
     $emit('someevent');

Homepage
    <Parent>
         <Child />
    </Parent>

how to catch an event?