Method which resets any variables held by this class, so that the parser can be used again
        :return: Nothing

def clear(self):
        '''
        Method which resets any variables held by this class, so that the parser can be used again
        :return: Nothing
        '''

        self.tags = []
        '''the current list of tags which have been opened in the XML file'''

        self.chars = {}
        '''the chars held by each tag, indexed by their tag name'''

        self.attribs = {}
        '''the attributes of each tag, indexed by their tag name'''

        self.handler = None
        ''' the method which will handle the current tag, and the data currently in the class '''

        self.piece = PieceTree.PieceTree()
        '''the class tree top'''

        self.isDynamic = False
        '''Indicator of whether the current thing being processed is a dynamic'''

        self.data["note"] = None
        self.data["direction"] = None
        self.data["expression"] = None
        self.data["degree"] = None
        self.data["frame_note"] = None
        self.data["staff_id"] = 1
        self.data["voice"] = 1
        self.data["handleType"] = ""