def clean(self, value):
        value = super(ITVatNumberField, self).clean(value)
        if value in EMPTY_VALUES:
            return ''
        try:
            return vat_number_validation(value)
        except __HOLE__:
            raise ValidationError(self.error_messages['invalid'])
dataset/ETHPy150Open django/django-localflavor/localflavor/it/forms.py/ITVatNumberField.clean