def _dataslice(self, data, indices):
        if isinstance(data, Dimensioned) and indices:
            return data[indices]
        elif len(indices) > 0:
            self.warning('Cannot index into data element, extra data'
                         ' indices ignored.')
        return data
Returns slice of data element if the item is deep
dataset/ETHPy150Open ioam/holoviews/holoviews/core/ndmapping.py/MultiDimensionalMapping._dataslice