attempt to make django checkboxes horizontal

horizontal_checkboxes.py

class SomeModelForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(MessageModelForm, self).__init__(*args, **kwargs)
        for f in self.fields.values():
            if isinstance(f.widget, widgets.CheckboxInput):
                f.widget.attrs.update({'class': "checkbox inline"})