def label(self, index, *args):
        """
        Label each axes one at a time
        args are of the form <label 1>,...,<label n>
        APIPARAM: chxl
        """
        self.data['labels'].append(
            str('%s:|%s'%(index, '|'.join(map(str,args)) )).replace('None','')
        )
        return self.parent
Label each axes one at a time
        args are of the form <label 1>,...,<label n>
        APIPARAM: chxl