<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def label_for_lm(self, **kwargs):
        "A special labelling method for language models."
        self.__class__ = LMTextList
        kwargs['label_cls'] = LMLabelList
        return self.label_const(0, **kwargs)