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    def reindex(self, *args, **kwargs):        # construct the args        axes, kwargs = self._construct_axes_from_arguments(args, kwargs)        method = missing.clean_reindex_fill_method(kwargs.pop('method', None))        '''        下面的代码，最是精妙        '''        level = kwargs.pop('level', None)        copy = kwargs.pop('copy', True)        limit = kwargs.pop('limit', None)        tolerance = kwargs.pop('tolerance', None)        fill_value = kwargs.pop('fill_value', np.nan)        if kwargs:            raise TypeError('reindex() got an unexpected keyword '                            'argument "{0}"'.format(list(kwargs.keys())[0]))        self._consolidate_inplace()        # if all axes that are requested to reindex are equal, then only copy        # if indicated must have index names equal here as well as values        if all([self._get_axis(axis).identical(ax)                for axis, ax in axes.items() if ax is not None]):            if copy:                return self.copy()            return self        # check if we are a multi reindex        if self._needs_reindex_multi(axes, method, level):            try:                return self._reindex_multi(axes, copy, fill_value)            except:                pass        # perform the reindex on the axes        return self._reindex_axes(axes, level, limit, tolerance, method,                                  fill_value, copy).__finalize__(self)