Toggle method not working

This is my html file:

<label class="toggle toggle-init">
  <input type="checkbox">
  <span class="toggle-icon"></span>
</label>

and this is app.js file:
var toggle = app.toggle.get(’.toggle’); ==> but this return undefined.

if (toggle.checked) {
console.log(“ok!”)
}

I use Framework7 V5.
Might you check my code and give me some advice? Thanks.