'Validate a phone number. Strips parentheses, whitespace and hyphens.'

def clean(self, value):

    super(AUPhoneNumberField, self).clean(value)
    if (value in EMPTY_VALUES):
        return u''
    value = re.sub('(\\(|\\)|\\s+|-)', '', smart_unicode(value))
    phone_match = PHONE_DIGITS_RE.search(value)
    if phone_match:
        return (u'%s' % phone_match.group(1))
    raise ValidationError(self.error_messages['invalid'])
