def clean(self, value):
        super(CHPhoneNumberField, self).clean(value)
        if value in EMPTY_VALUES:
            return ''
        value = re.sub('(\.|\s|/|-)', '', force_text(value))
        m = phone_digits_re.search(value)
        if m:
            return '%s %s %s %s' % (value[0:3], value[3:6], value[6:8], value[8:10])
        raise ValidationError(self.error_messages['invalid'])
dataset/ETHPy150Open django/django-localflavor/localflavor/ch/forms.py/CHPhoneNumberField.clean/original