Sunburst branchvalues parameter

I’m struggling to use the sunburst graph object in a Jupyter notebook. It’s perfect for my use case (spread of file formats in a given corpus), however using the parameter branchvalues=‘total’ gives me just a white box.
A dodgy workaround setting the parent values to 0 gives me this:

which is how it should look. I’ve rechecked my data several times, the combined value of children adds up foreach parent.

trace = go.Sunburst(
    outsidetextfont = {"size": 20, "color": "#377eb8"},
    marker = {"line": {"width": 2}},
layout = go.Layout(
    margin = go.layout.Margin(t=0, l=0, r=0, b=0, )
iplot(go.Figure([trace], layout), filename='format_spread')