def _dir_additions(self):
additions = {c for c in self._info_axis.unique(level=<NUM_LIT:0>)[:<NUM_LIT:100>]<EOL>if isinstance(c, str) and c.isidentifier()}<EOL>return super()._dir_additions().union(additions)<EOL>
add the string-like attributes from the info_axis.
        If info_axis is a MultiIndex, it's first level values are used.