Rounded corners for px.timeline gantt charts

📊 Plotly Python
1

Any idea how to add rounded corners to Plotly Express px.timeline gantt charts?
I have a gantt chart like this:

fig_model = px.timeline(df, x_start="Start", x_end="End", y="Machine", facet_row="Source",
                            color="Acronym")

Have tried adding the path from https://codepen.io/alexcjohnson/pen/dErOaK?editors=0010, referenced in this topic to fig_model.update_shapes() but this seems to add a different layer to the gantt chart:

    ply_shapes = {}
    for i in range(1, len(df)):
        ply_shapes['shape_' + str(i)] = go.layout.Shape(type="line",
                                                        x0=df['Start'].iloc[i],
                                                        y0=df['Machine'].iloc[i - 1],
                                                        x1=df['End'].iloc[i],
                                                        y1=df['Machine'].iloc[i - 1],

                                                        )
    lst_shapes = list(ply_shapes.values())
    fig_model.update_layout(shapes=lst_shapes)

Is there a way to change shapes of bar charts within the px.timeline figure? While keeping the colors?
Thanks!