Display radio button in django?

Hi, I have this problem ... I can not manage to display the radio button in the template ... in which I'm wrong?

models.py

class Genero(models.Model):

    MASCULINO ='mas'

    FEMENINO ='fem'
    Type_CHOICES = (
    (MASCULINO,'masculino'),
    (FEMENINO,'femenino'))
    sexo = models.CharField(choices=Type_CHOICES,default=MASCULINO, max_length=100)

form.py

class VideoForm(forms.ModelForm):

    class Meta:
        model=Genero
        fields=['sexo']
        widgets = {
        'sexo': forms.RadioSelect(choices=Video.Type_CHOICES)           

}

template

{% for radio in sexo %}

    <label >
        {{ radio }}
        <span> {{ radio.tag }} </span>
    </label>

{% endfor %}