How to define callbacks in separate files? (plotly dash)

A little late to the party but I have found this to be a straightforward way of doing it:

1. You create a separate script called ‘callbacks.py’ (for example)
2. Define a function within callbacks.py which takes a dash.Dash object (i.e. the app) as a parameter (you can of course pass more arguments if necessary) and within which you define all your callbacks as you normally would in the main script:

def get_callbacks(app):
    @app.callback([Output("figure1", "figure")],
                  [Input("child1", "value")])
    def callback1(figure):
        return

    @app.callback([Output("figure2", "figure")],
                  [Input("child2", "value")])
    def callback2(figure):
        return

3. Within the main script, simply import the function and call it after instantiating the dash.Dash object passing the same object into it:

import dash
from callbacks import get_callbacks
import layout

app = dash.Dash(__name__)
app.layout = layout.layout

get_callbacks(app)