def save_form(self, commit=True):
        """
        This calls Django's ``ModelForm.save()``. It only takes care of
        saving this actual form, and leaves the nested forms and formsets
        alone.

        We separate this out of the
        :meth:`~django_superform.forms.SuperModelForm.save` method to make
        extensibility easier.
        """
        return super(SuperModelFormMixin, self).save(commit=commit)