def _get_lazy_indices(self):
        """This method creates indices on-the-fly if self._indices=None.
        Only for internal use. Call may be expensive if self._indices=None.
        """
        if self._indices is not None:
            return self._indices
        else:
            return LazyRange(0, len(self))
This method creates indices on-the-fly if self._indices=None.
        Only for internal use. Call may be expensive if self._indices=None.
        
avalanche/benchmarks/utils/flat_data.py