How to use the idna.core.IDNAError function in idna

class IDNAError(UnicodeError):
    """ Base exception for all IDNA-encoding related problems """
    pass


class IDNABidiError(IDNAError):
    """ Exception when bidirectional requirements are not satisfied """
    pass


class InvalidCodepoint(IDNAError):
    """ Exception when a disallowed or unallocated codepoint is used """
    pass


class InvalidCodepointContext(IDNAError):
    """ Exception when the codepoint is not valid in the context it is used """
    pass


def _combining_class(cp):
    v = unicodedata.combining(unichr(cp))
    if v == 0:
        if not unicodedata.name(unichr(cp)):
            raise ValueError("Unknown character in unicodedata")
    return v

def _is_script(cp, script):
    return intranges_contain(ord(cp), idnadata.scripts[script])

def _punycode(s):
    return s.encode('punycode')

from .intranges import intranges_contain

_virama_combining_class = 9
_alabel_prefix = b'xn--'
_unicode_dots_re = re.compile(u'[\u002e\u3002\uff0e\uff61]')

if sys.version_info[0] == 3:
    unicode = str
    unichr = chr

class IDNAError(UnicodeError):
    """ Base exception for all IDNA-encoding related problems """
    pass


class IDNABidiError(IDNAError):
    """ Exception when bidirectional requirements are not satisfied """
    pass


class InvalidCodepoint(IDNAError):
    """ Exception when a disallowed or unallocated codepoint is used """
    pass


class InvalidCodepointContext(IDNAError):
    """ Exception when the codepoint is not valid in the context it is used """
    pass


def _combining_class(cp):
    v = unicodedata.combining(unichr(cp))

def check_nfc(label):

    if unicodedata.normalize('NFC', label) != label:
        raise IDNAError('Label must be in Normalization Form C')

def alabel(label):

    try:
        label = label.encode('ascii')
        ulabel(label)
        if not valid_label_length(label):
            raise IDNAError('Label too long')
        return label
    except UnicodeEncodeError:
        pass

    if not label:
        raise IDNAError('No Input')

    label = unicode(label)
    check_label(label)
    label = _punycode(label)
    label = _alabel_prefix + label

    if not valid_label_length(label):
        raise IDNAError('Label too long')

    return label

def decode(self, data, errors='strict'):

        if errors != 'strict':
            raise IDNAError("Unsupported error handling \"{0}\"".format(errors))

        if not data:
            return u"", 0

        return decode(data), len(data)

check_nfc(label)
    check_hyphen_ok(label)
    check_initial_combiner(label)

    for (pos, cp) in enumerate(label):
        cp_value = ord(cp)
        if intranges_contain(cp_value, idnadata.codepoint_classes['PVALID']):
            continue
        elif intranges_contain(cp_value, idnadata.codepoint_classes['CONTEXTJ']):
            try:
                if not valid_contextj(label, pos):
                    raise InvalidCodepointContext('Joiner {0} not allowed at position {1} in {2}'.format(
                        _unot(cp_value), pos+1, repr(label)))
            except ValueError:
                raise IDNAError('Unknown codepoint adjacent to joiner {0} at position {1} in {2}'.format(
                    _unot(cp_value), pos+1, repr(label)))
        elif intranges_contain(cp_value, idnadata.codepoint_classes['CONTEXTO']):
            if not valid_contexto(label, pos):
                raise InvalidCodepointContext('Codepoint {0} not allowed at position {1} in {2}'.format(_unot(cp_value), pos+1, repr(label)))
        else:
            raise InvalidCodepoint('Codepoint {0} at position {1} of {2} not allowed'.format(_unot(cp_value), pos+1, repr(label)))

    check_bidi(label)

def check_label(label):

    if isinstance(label, (bytes, bytearray)):
        label = label.decode('utf-8')
    if len(label) == 0:
        raise IDNAError('Empty Label')

    check_nfc(label)
    check_hyphen_ok(label)
    check_initial_combiner(label)

    for (pos, cp) in enumerate(label):
        cp_value = ord(cp)
        if intranges_contain(cp_value, idnadata.codepoint_classes['PVALID']):
            continue
        elif intranges_contain(cp_value, idnadata.codepoint_classes['CONTEXTJ']):
            try:
                if not valid_contextj(label, pos):
                    raise InvalidCodepointContext('Joiner {0} not allowed at position {1} in {2}'.format(
                        _unot(cp_value), pos+1, repr(label)))
            except ValueError:
                raise IDNAError('Unknown codepoint adjacent to joiner {0} at position {1} in {2}'.format(

def check_hyphen_ok(label):

    if label[2:4] == '--':
        raise IDNAError('Label has disallowed hyphens in 3rd and 4th position')
    if label[0] == '-' or label[-1] == '-':
        raise IDNAError('Label must not start or end with a hyphen')
    return True

def alabel(label):

    try:
        label = label.encode('ascii')
        ulabel(label)
        if not valid_label_length(label):
            raise IDNAError('Label too long')
        return label
    except UnicodeEncodeError:
        pass

    if not label:
        raise IDNAError('No Input')

    label = unicode(label)
    check_label(label)
    label = _punycode(label)
    label = _alabel_prefix + label

    if not valid_label_length(label):
        raise IDNAError('Label too long')

    return label