How to use the vcard.vcard_errors.VCardError function in vcard

def test_valid(self):
        """Valid (but not necessarily sane) vCards"""
        for vcard_file in VCARDS_VALID:
            vcard_text = _get_vcard_file(vcard_file)
            if vcard_text is None:
                continue

            try:
                with warnings.catch_warnings(record=True):
                    vc_obj = vcard_validator.VCard(vcard_text, filename=vcard_file)
                self.assertNotEqual(vc_obj, None)
            except vcard_errors.VCardError as error:
                error_message = '\n\n'.join((
                    'Expected valid vCard for {vcard_file!r}, but it failed to validate'.format(
                        vcard_file=vcard_file
                    ),
                    str(error)
                ))
                self.fail(error_message)

if len(value) != 1:
                        raise VCardItemCountError(
                            '{0}: {1:d} (expected 1)'.format(
                                NOTE_INVALID_SUB_VALUE_COUNT, len(property_.values[0])), {})
                    validate_uri(value[0])
            else:
                # Inline vCard object
                pass  # TODO: Un-escape and validate value

        elif property_name == 'URL':
            # 
            _expect_no_parameters(property_)
            _expect_value_count(property_.values, 1)
            validate_uri(property_.values[0][0])

    except VCardError as error:
        error.context['Property'] = property_name
        err_type = type(error)
        raise err_type(error.message, error.context)

message += '\n{0}: {1}'.format(_stringify(key), _stringify(self.context.pop(key)))

        return message


class VCardLineError(VCardError):
    """Raised for line-related errors."""
    pass


class VCardNameError(VCardError):
    """Raised for name-related errors."""
    pass


class VCardValueError(VCardError):
    """Raised for value-related errors."""
    pass


class VCardItemCountError(VCardError):
    """Raised when a required number of something is not present."""
    pass


class UsageError(Exception):
    """Raise in case of invalid parameters."""
    def __init__(self, message):
        Exception.__init__(self)
        self._message = message

    def __str__(self):

def __init__(self, text, filename=None):
        """
        Create vCard object from text string. Includes text (the entire
        unprocessed vCard), group (optional prefix on each line) and
        properties.

        @param text: String containing a single vCard
        """
        if text == '' or text is None:
            raise VCardError(NOTE_EMPTY_VCARD, {'vCard line': 1, 'File line': 1})

        self.text = text

        self.filename = filename

        lines = unfold_vcard_lines(self.text.splitlines(True))

        # Groups
        self.group = get_vcard_group(lines)
        lines = remove_vcard_groups(lines, self.group)

        # Properties
        self.properties = get_vcard_properties(lines)

# Sort context information
        keys = ['File', 'File line', 'vCard line', 'Property', 'Property line', 'String']
        for key in keys:
            if key in self.context:
                message += '\n{0}: {1}'.format(_stringify(key), _stringify(self.context.pop(key)))

        return message


class VCardLineError(VCardError):
    """Raised for line-related errors."""
    pass


class VCardNameError(VCardError):
    """Raised for name-related errors."""
    pass


class VCardValueError(VCardError):
    """Raised for value-related errors."""
    pass


class VCardItemCountError(VCardError):
    """Raised when a required number of something is not present."""
    pass


class UsageError(Exception):
    """Raise in case of invalid parameters."""

def get_vcard_properties(lines):
    """
    Get the properties for each line. RFC 2426 pages 28, 29.

    @param lines: List of unfolded vCard lines
    @return: List of properties, for simplicity. AFAIK sequence doesn't matter
    and duplicates add no information, but ignoring this to make sure vCard
    output looks like the original.
    """
    properties = []
    for index in range(len(lines)):
        property_line = lines[index]
        if property_line != NEWLINE_CHARACTERS:
            try:
                properties.append(get_vcard_property(property_line))
            except VCardError as error:
                error.context['vCard line'] = index
                err_type = type(error)
                raise err_type(
                    error.message,
                    error.context)

    for mandatory_property in MANDATORY_PROPERTIES:
        if mandatory_property not in [property_.name.upper() for property_ in properties]:
            raise VCardItemCountError(
                '{0}: {1}'.format(NOTE_MISSING_PROPERTY, mandatory_property), {'Property': mandatory_property})

    return properties

class VCardLineError(VCardError):
    """Raised for line-related errors."""
    pass


class VCardNameError(VCardError):
    """Raised for name-related errors."""
    pass


class VCardValueError(VCardError):
    """Raised for value-related errors."""
    pass


class VCardItemCountError(VCardError):
    """Raised when a required number of something is not present."""
    pass


class UsageError(Exception):
    """Raise in case of invalid parameters."""
    def __init__(self, message):
        Exception.__init__(self)
        self._message = message

    def __str__(self):
        return self._message

Outputs error with ordered context info.

        @return: Printable error message
        """
        message = _stringify(self.message)

        # Sort context information
        keys = ['File', 'File line', 'vCard line', 'Property', 'Property line', 'String']
        for key in keys:
            if key in self.context:
                message += '\n{0}: {1}'.format(_stringify(key), _stringify(self.context.pop(key)))

        return message


class VCardLineError(VCardError):
    """Raised for line-related errors."""
    pass


class VCardNameError(VCardError):
    """Raised for name-related errors."""
    pass


class VCardValueError(VCardError):
    """Raised for value-related errors."""
    pass


class VCardItemCountError(VCardError):
    """Raised when a required number of something is not present."""