No module named 'tkinter'

As far I undertood, to use a debian package from apt, in runtime, I only need to add the name of package in stage-packages.
It seems It worked, my snap contains the package.
But if I shell my virtual machine using: multipass shell snapcraft-tkedit And I try calling Python3 <> that uses the package, It returns ModuleNotFoundError.

my snapcraft.yaml

    name: tkedit 
    type: "app"
    base: core20
            command: bin/tkedit
                source: /home/element/tkedit
                source-type: local
                plugin: python
                stage-packages: [python3-tk]

When installing the environment, the message appears ok:
Get:1 python3-tk_3.8.10-0ubuntu1~20.04_amd64.deb [104 kB]
Fetched 0 B in 0s (0 B/s)

When I call the app from my shell in my host OS:

    ❯ tkedit
    Traceback (most recent call last):
      File "/snap/tkedit/x3/bin/tkedit", line 5, in <module>
        from texteditor import main
      File "/snap/tkedit/x3/lib/python3.8/site-packages/", line 2, in <module>
        import tkinter as tk
    ModuleNotFoundError: No module named 'tkinter'

the module is in the folder: