I am using a simple checkbox in VUE JS but validation rule is not working

Checkbox Code

<div
  v-for="option in question.options"
  :key="reg.id+m+question.id+option.id">
  <label
    for="optionId"
    style="padding:10px;">
   {{option.value}}
  </label>

  <input
    type="checkbox"
    name="optionId"
    v-model="attendees[reg.id]['registration'][m].questions[question.id]"
    :value="option.id"
    :rules="[(value) => 
      questionsRequiredRuleCheckBoxes(
        value,
        question.required, 
        attendees[reg.id]['registration'][m].questions[question.id]
      )]"/>
</div>

validation rule

questionsRequiredRuleCheckBoxes: ( value, required, v_model ) => {
  if (required !== 1 || v_model.length >= 1) {
    return true;
  }

  return "At least one item is required.";
}