def dimension_values(self, dimension, expanded=True, flat=True):
        "Returns the values along the specified dimension."
        dimension = self.get_dimension(dimension, strict=True).name
        all_dims = self.traverse(lambda x: [d.name for d in x.dimensions()])
        if chain.from_iterable(all_dims) in dimension:
            values = [el.dimension_values(dimension) for el in self
                      if dimension in el.dimensions(label=True)]
            vals = np.concatenate(values)
            return vals if expanded else unique_array(vals)
        else:
            return super(Layout, self).dimension_values(dimension,
                                                        expanded, flat)
dataset/ETHPy150Open ioam/holoviews/holoviews/core/layout.py/Layout.dimension_values/swapped operands of `in`