Django - initial checked CheckboxInput

I want my CheckboxInput was checked by default :

My models :

class Sub(models.Model):
    user = models.OneToOneField(User)
    batata = models.BooleanField(default=False)

class presentationForm(forms.ModelForm):
    class Meta : 
        model = Sub
    widgets = {
        'batata': forms.CheckboxInput(attrs={'id':'batata'}),
    }
    def __init__(self, *args, **kwargs):
        self.valbata = kwargs.pop("arg_bata")
        super(presentationForm, self).__init__(*args, **kwargs)
        self.fields['batata'].initial = True

My view :

def theview(request):
    form = presentationForm(arg_bata="Azerty")
    return render(request,"le_site/page-batata.html",locals())

My template :

...
{{ form.batata|bootstrap }}
...

But in my page, the checbkoxInput "batata" isn't checked...