Vuetify tooltip in data table

I want to add some tool tip in a vuetify datatable , but nothing happen.

this is the template that I need to use a tool tip

<template v-slot:item.state="{ item }">
   <div :class="lights(item)"></div>
</template>

and I use it like this

<v-tooltip left>
      <template v-slot:activator="{ on }">
         <template v-slot:item.state="{ item }">
           <div :class="lights(item)"></div>
         </template>
      </template>
   <span>Tooltip</span>
</v-tooltip>

Some one can tell me what to do ?