How to use the elementpath.datatypes.GregorianDay function in elementpath

'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
    },   # 64 bit floating point
    {
        'name': XSD_FLOAT,
        'python_type': float,
        'admitted_facets': FLOAT_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
    },  # 32 bit floating point

    # --- Dates and Times (not year related) ---
    {
        'name': XSD_GDAY,
        'python_type': (unicode_type, str, datatypes.GregorianDay),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.GregorianDay.fromstring,
    },  # DD
    {
        'name': XSD_GMONTH,
        'python_type': (unicode_type, str, datatypes.GregorianMonth),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.GregorianMonth.fromstring,
    },  # MM
    {
        'name': XSD_GMONTH_DAY,
        'python_type': (unicode_type, str, datatypes.GregorianMonthDay),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.GregorianMonthDay.fromstring,
    },  # MM-DD
    {

'name': XSD_DOUBLE,
        'python_type': float,
        'admitted_facets': FLOAT_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
    },   # 64 bit floating point
    {
        'name': XSD_FLOAT,
        'python_type': float,
        'admitted_facets': FLOAT_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
    },  # 32 bit floating point

    # --- Dates and Times (not year related) ---
    {
        'name': XSD_GDAY,
        'python_type': (unicode_type, str, datatypes.GregorianDay),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.GregorianDay.fromstring,
    },  # DD
    {
        'name': XSD_GMONTH,
        'python_type': (unicode_type, str, datatypes.GregorianMonth),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],
        'to_python': datatypes.GregorianMonth.fromstring,
    },  # MM
    {
        'name': XSD_GMONTH_DAY,
        'python_type': (unicode_type, str, datatypes.GregorianMonthDay),
        'admitted_facets': DATETIME_FACETS,
        'facets': [COLLAPSE_WHITE_SPACE_ELEMENT],