Sankey Plot Node Positions are incorrect

Describe your context

• replace the result of pip list | grep dash below

dash                 1.5.1              
dash-core-components 1.4.0              
dash-html-components 1.0.1              
dash-renderer        1.2.0              
dash-table           4.5.0  

Describe the bug

Want to position Nodes along X-Axis in a Sankey Plot and Y to be automatically Adjusted. When I define X Positions only Sankey doesn't align the Nodes. But If I define Y Positions then only Sankey aligns the Nodes.

    def create_sankey_plot(self, source_r, target_r, value_r, colors_r,
                           labels_r, labels_a, colors_a):
        return go.Sankey(
            node=dict(
                pad=15,
                thickness=20,
                line=dict(color="black", width=0.5),
                label=labels_a,
                color=colors_a,
                x=[0.2, 0.1, 0.5, 0.7, 0.3, 0.5]
            ),
            link=dict(
                source=source_r,
                target=target_r,
                value=value_r,
                color=colors_r,
                line={'width': 1},
                label=labels_r
            )
        )

Above code will not align Nodes. Below code works:

def create_sankey_plot(self, source_r, target_r, value_r, colors_r,
                           labels_r, labels_a, colors_a):
        return go.Sankey(
            node=dict(
                pad=15,
                thickness=20,
                line=dict(color="black", width=0.5),
                label=labels_a,
                color=colors_a,
                x=[0.2, 0.1, 0.5, 0.7, 0.3, 0.5],
                y=[0.3, 0.3, 0.3, 0.3, 0.3, 0.3],
            ),
            link=dict(
                source=source_r,
                target=target_r,
                value=value_r,
                color=colors_r,
                line={'width': 1},
                label=labels_r
            )
        )

Expected behavior

Align Nodes if provided only X values / Y values making other default.

Inizia riproducendo il caso go.Sankey segnalato usando solo valori di node.x, quindi confrontalo con l'esempio che fornisce anche valori di node.y. Analizza la gestione delle posizioni dei nodi Sankey esposta dalla Python API e verifica che fornire una sola coordinata continui ad allineare i nodi mentre l'altra viene regolata automaticamente.