Can anyone explain this error message? ImportError: cannot import name 'callback' from 'dash'

Dash Python
1

I have not made any significant changes, but I am suddenly receiving this error message. I added the statement "from dash import callback’ to each page with callbacks when I converted my app to a multi-page app days ago.

It has worked fine, more or less, as a multi-page app since then.

A search of this platform for this message produced no results, and a Google search search produced no results for this message either. I just don’t know what could cause it, so I have to ask a general question.

I am hoping maybe someone out there has tangled with his one already and knows the answer?

Here is a copy of the entire Traceback message.

It does not reference a page or line number in my code, though it does reference the init.py page in the Dash site package. That does not leave me with much of a starting point.

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2

Never mind.

I figured it out. I had made a change that inadvertently led to installing a previous version of Dash.

You must be running the current version, Dash 2.0, for import callbacks to work.

It is working fine now.

Thanks.

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3

I don’ think I’ve ever had to from dash import callback before. Out of curiosity, how are you using that?

I’ve definitely used from dash import callback_context

4

For reference, here is the documentation regarding callbacks in v2.0:

It is mainly a convenience to avoid importing app when splitting the app in multiple modules (like for Multi-Page Apps).

5

Huh, learn something new everyday, did not know this.

Each page of my app has from app import app in every file on my multipage app. Will definitely be testing this!

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