Django Many to Many CheckboxSelectMultiple

forms.py

from django.forms.widgets import CheckboxSelectMultiple
from django import forms

from .models import Curriculo


class CurriculoForm(forms.ModelForm):
  
  class Meta:
    model = Curriculo
    widgets = {
      "habilidades": CheckboxSelectMultiple
    }

models.py

class Curriculo(models.Model):
      habilidades  = models.ManyToManyField(Habilidade, through='CurriculosHabilidades')

class Habilidade(models.Model):
     tipo    = models.IntegerField(choices=HABILIDADES_CHOICES)
     nome  = models.CharField(max_length=100,verbose_name=_('Nome'))

class CurriculosHabilidades(models.Model):  
    curriculo         = models.ForeignKey(Curriculo)
    habilidade      = models.ForeignKey(Habilidade)
    nivel               = models.IntegerField(choices=HABILIDADES_NIVEIS_CHOICES)