How to use the elementpath.datatypes function in elementpath

'python_type': (unicode_type, str),
        'base_type': XSD_DATETIME,
        'to_python': datatypes.DateTime.fromstring,
        'facets': [etree_element(XSD_EXPLICIT_TIMEZONE, value='required')],
    },  # [-][Y*]YYYY-MM-DD[Thh:mm:ss] with required timezone
    {
        'name': XSD_DAY_TIME_DURATION,
        'python_type': (unicode_type, str),
        'base_type': XSD_DURATION,
        'to_python': datatypes.DayTimeDuration.fromstring,
    },  # PnYnMnDTnHnMnS with month an year equal to 0
    {
        'name': XSD_YEAR_MONTH_DURATION,
        'python_type': (unicode_type, str),
        'base_type': XSD_DURATION,
        'to_python': datatypes.YearMonthDuration.fromstring,
    },  # PnYnMnDTnHnMnS with day and time equals to 0
    # --- xs:error primitive type (XSD 1.1) ---
    {
        'name': XSD_ERROR,
        'python_type': type(None),
        'admitted_facets': (),
        'facets': [error_type_validator],
    },  # xs:error has no value space and no lexical space
)


def xsd_builtin_types_factory(meta_schema, xsd_types, atomic_builtin_class=None):
    """
    Builds the dictionary for XML Schema built-in types mapping.
    """
    atomic_builtin_class = atomic_builtin_class or XsdAtomicBuiltin

def _parse(self):
        super(XsdFacet, self)._parse()
        try:
            self.path = self.elem.attrib['test']
        except KeyError as err:
            self.parse_error(str(err), elem=self.elem)
            self.path = 'true()'

        try:
            builtin_type_name = self.base_type.primitive_type.local_name
            variables = {'value': datatypes.XSD_BUILTIN_TYPES[builtin_type_name].value}
        except AttributeError:
            variables = {'value': datatypes.XSD_BUILTIN_TYPES['anySimpleType'].value}

        if 'xpathDefaultNamespace' in self.elem.attrib:
            self.xpath_default_namespace = self._parse_xpath_default_namespace(self.elem)
        else:
            self.xpath_default_namespace = self.schema.xpath_default_namespace
        self.parser = XPath2Parser(self.namespaces, strict=False, variables=variables,
                                   default_namespace=self.xpath_default_namespace)

        try:
            self.token = self.parser.parse(self.path)
        except ElementPathError as err:
            self.parse_error(err, elem=self.elem)
            self.token = self.parser.parse('true()')

'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.GregorianYearMonth.fromstring,
    },  # [-][Y*]YYYY-MM
    # --- Datetime derived types (XSD 1.1) ---
    {
        'name': XSD_DATE_TIME_STAMP,
        'python_type': (unicode_type, str),
        'base_type': XSD_DATETIME,
        'to_python': datatypes.DateTime.fromstring,
        'facets': [etree_element(XSD_EXPLICIT_TIMEZONE, value='required')],
    },  # [-][Y*]YYYY-MM-DD[Thh:mm:ss] with required timezone
    {
        'name': XSD_DAY_TIME_DURATION,
        'python_type': (unicode_type, str),
        'base_type': XSD_DURATION,
        'to_python': datatypes.DayTimeDuration.fromstring,
    },  # PnYnMnDTnHnMnS with month an year equal to 0
    {
        'name': XSD_YEAR_MONTH_DURATION,
        'python_type': (unicode_type, str),
        'base_type': XSD_DURATION,
        'to_python': datatypes.YearMonthDuration.fromstring,
    },  # PnYnMnDTnHnMnS with day and time equals to 0
    # --- xs:error primitive type (XSD 1.1) ---
    {
        'name': XSD_ERROR,
        'python_type': type(None),
        'admitted_facets': (),
        'facets': [error_type_validator],
    },  # xs:error has no value space and no lexical space
)

def qname_validator(x):
    if datatypes.QNAME_PATTERN.match(x) is None:
        yield XMLSchemaValidationError(qname_validator, x, "value {!r} is not an xs:QName".format(x))

'name': XSD_GYEAR_MONTH,
        'python_type': (unicode_type, str, datatypes.GregorianYearMonth10),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.GregorianYearMonth10.fromstring,
    },  # [-][Y*]YYYY-MM
)

XSD_11_BUILTIN_TYPES = XSD_COMMON_BUILTIN_TYPES + (
    # --- Year related primitive types (year 0 allowed and mapped to 1 BCE) ---
    {
        'name': XSD_DATETIME,
        'python_type': (unicode_type, str, datatypes.DateTime),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.DateTime.fromstring,
    },  # [-][Y*]YYYY-MM-DD[Thh:mm:ss]
    {
        'name': XSD_DATE,
        'python_type': (unicode_type, str, datatypes.Date),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.Date.fromstring,
    },  # [-][Y*]YYYY-MM-DD
    {
        'name': XSD_GYEAR,
        'python_type': (unicode_type, str, datatypes.GregorianYear),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.GregorianYear.fromstring,
    },  # [-][Y*]YYYY
    {