How to use the parsedatetime.__init__.Constants function in parsedatetime

def __init__(self, constants=None):
        """
        Default constructor for the L{Calendar} class.

        @type  constants: object
        @param constants: Instance of the class L{parsedatetime_consts.Constants}

        @rtype:  object
        @return: L{Calendar} instance
        """
          # if a constants reference is not included, use default
        if constants is None:
            self.ptc = Constants()
        else:
            self.ptc = constants

        self.weekdyFlag    = False  # monday/tuesday/...
        self.dateStdFlag   = False  # 07/21/06
        self.dateStrFlag   = False  # July 21st, 2006
        self.timeStdFlag   = False  # 5:50
        self.meridianFlag  = False  # am/pm
        self.dayStrFlag    = False  # tomorrow/yesterday/today/..
        self.timeStrFlag   = False  # lunch/noon/breakfast/...
        self.modifierFlag  = False  # after/before/prev/next/..
        self.modifier2Flag = False  # after/before/prev/next/..
        self.unitsFlag     = False  # hrs/weeks/yrs/min/..
        self.qunitsFlag    = False  # h/m/t/d..

        self.timeFlag      = 0

def __init__(self, constants=None):
        """
        Default constructor for the L{Calendar} class.

        @type  constants: object
        @param constants: Instance of the class L{Constants}

        @rtype:  object
        @return: L{Calendar} instance
        """
        # if a constants reference is not included, use default
        if constants is None:
            self.ptc = Constants()
        else:
            self.ptc = constants

        self.weekdyFlag = False  # monday/tuesday/...
        self.dateStdFlag = False  # 07/21/06
        self.dateStrFlag = False  # July 21st, 2006
        self.timeStdFlag = False  # 5:50
        self.meridianFlag = False  # am/pm
        self.dayStrFlag = False  # tomorrow/yesterday/today/..
        self.timeStrFlag = False  # lunch/noon/breakfast/...
        self.modifierFlag = False  # after/before/prev/next/..
        self.modifier2Flag = False  # after/before/prev/next/..
        self.unitsFlag = False  # hrs/weeks/yrs/min/..
        self.qunitsFlag = False  # h/m/t/d..

        self.timeFlag = 0

"""
        Default constructor for the L{Calendar} class.

        @type  constants: object
        @param constants: Instance of the class L{Constants}
        @type  version:   integer
        @param version:   Default style version of current Calendar instance.
                          Valid value can be 1 (L{VERSION_FLAG_STYLE}) or
                          2 (L{VERSION_CONTEXT_STYLE}). See L{parse()}.

        @rtype:  object
        @return: L{Calendar} instance
        """
        # if a constants reference is not included, use default
        if constants is None:
            self.ptc = Constants()
        else:
            self.ptc = constants

        self.version = version
        if version == VERSION_FLAG_STYLE:
            warnings.warn(
                'Flag style will be deprecated in parsedatetime 2.0. '
                'Instead use the context style by instantiating `Calendar()` '
                'with argument `version=parsedatetime.VERSION_CONTEXT_STYLE`.',
                pdt20DeprecationWarning)
        self._ctxStack = pdtContextStack()