How to trigger a mouseout event in Python Dash?

Dash Python
1

How can I implement a callback function that reacts to mouseout and restores a default when not hovering over a data point?

I simplified a code snipped from the ‘Interactive Visualizations’ section of the Plotly|Dash tutorial to illustrate my question. In this example a callback function returns the mouseover information. How do I return something else on mouseout?

import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output
import plotly.express as px
import pandas as pd

app = dash.Dash(__name__)

df = pd.DataFrame({
    "x": [1,2,1,2],
    "y": [1,2,3,4]
})

fig = px.scatter(df, x="x", y="y")

fig.update_traces(marker_size=20)

app.layout = html.Div([
    dcc.Graph(
        id='basic-interactions',
        figure=fig
    ),
    html.Div([
        html.Pre(id='hover-data')
    ])
])

@app.callback(
    Output('hover-data', 'children'),
    Input('basic-interactions', 'hoverData'))
def display_hover_data(hoverData):
    if hoverData:
        return str(hoverData)
    else:
        return "hover over data point"

if __name__ == '__main__':
    app.run_server(debug=True)