def METHOD_NAME(self, organisation, div, subtype=None):
    field_id = "__".join(
        [str(x) for x in [organisation.pk, div.pk, subtype] if x]
    )
    field = forms.ChoiceField(
        choices=self.choices,
        widget=dc_forms.RadioSelectCluster,
        label=div.name,
        initial="no_seats",
        required=False,
    )
    self.fields[field_id] = field