dash.exceptions.InvalidCallbackReturnValue: The callback ..graph-peer-universe.figure.. is a multi-output

Dash Python
1

I’ve tried to modify the example of generating a scatter from a callback found here: https://dash.plot.ly/getting-started-part-2

I keep getting this exception raised.

dash.exceptions.InvalidCallbackReturnValue: The callback …graph-peer-universe.figure… is a multi-output.
Expected the output type to be a list or tuple but got {‘data’: [Scatter({
‘marker’: {‘line’: {‘color’: ‘white’, ‘width’: 0.5}, ‘size’: 15},
‘mode’: ‘markers’,
‘name’: ‘Corporate’,
‘opacity’: 0.7,
‘text’: array([‘Goldman Sachs & JBWere Superannuation - MySuper’,
‘QANTAS Super Gateway MySuper - Glidepath Take-Off’,
‘Telstra Super - MySuper Growth’], dtype=object),
‘x’: array([0.09322128, 0.07920195, 0.06869553]),
‘y’: array([750., 552., 638.])
})], ‘layout’: Layout({
‘hovermode’: ‘closest’, ‘legend’: {‘x’: 0, ‘y’: 1}
})}.

I’m very confident but just cant figure out whats wrong.

My function for the callback:

    def graph_peer_universe(data, hidden, fund_types, asset_class, investment_name, fund_access, strategy, xaxis, yaxis, color):
    data = return_table(data, hidden, fund_types, asset_class, investment_name, fund_access, strategy, convert_to_dict=False)

    traces = []

    for i in data[color].unique():
        df_by_color = data[data[color] == i]
        traces.append(go.Scatter(
            x=df_by_color[xaxis],
            y=df_by_color[yaxis],
            text=df_by_color['investment_name'],
            mode='markers',
            opacity=0.7,
            marker={
                'size': 15,
                'line': {'width': 0.5, 'color': 'white'}
            },
            name=i
        ))

    return {
        'data': traces,
        'layout': go.Layout(
            legend={'x': 0, 'y': 1},
            hovermode='closest'
        )
    }

My callback

@app.callback([Output('graph-peer-universe', 'figure')],
            [Input('hidden-data-radio', "value"),
            Input('fund-types-dropdown', 'value'),
            Input('asset-class-dropdown', 'value'),
            Input('name-search', 'value'),
            Input('fund-access-checklist', 'value'),
            Input('strategy-checklist', 'value'),
            Input('x-axis-dropdown', 'value'),
            Input('y-axis-dropdown', 'value'),
            Input('color-dropdown', 'value'),
            ])
def return_size_table(hidden, fund_types, asset_class,  investment_name, fund_access, strategy, x_axis, y_axis, color):
    return graph_peer_universe(df, hidden, fund_types, asset_class, investment_name, fund_access, strategy, x_axis, y_axis, color)

app.py
dcc.Graph(id="graph-peer-universe")

2

Change this to
@app.callback(Output(‘graph-peer-universe’, ‘figure’),

or wrap whatever you are returning in your callback in a list.

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