Multiselect en el admin

multiselect_admin.py

class NotificationORMForm(forms.ModelForm):
    ...

    class Meta:
        model = NotificationORM
        fields = (
            'tenant',
            ...
        )
        widgets = {
            'strategies': ArrayFieldSelectMultiple(
                verbose_name=_('Strategies'),
                attrs={'class': 'chosen'},
                choices=NotificationStrategy.choices(),
            ),
        }