setting `python-shell-interpreter-args' based on virtualenv

[spluque]

I have python-shell-interpreter set to jupyter, and python-shell-interpreter-args to:

console --kernel python3 --simple-prompt

I have jupyter and a python3 kernel installed in several virtualenvs. Unfortunately, activating the virtualenv with pyvenv-workon myvenv runs the python3 kernel from the main environment (not myvenv).

This is what elpy-config shows with myvenv activated:

Emacs.............: 26.1
Elpy..............: 1.32.0
Virtualenv........:  (/home/joe/.virtualenvs/myvenv/)
Interactive Python: jupyter 4.6.1 (/home/joe/.virtualenvs/myvenv/bin/jupyter)
RPC virtualenv....: elpy-rpc-venv (/home/joe/.virtualenvs/elpy-rpc-venv)
 Python...........: python3 3.7.4 (/home/joe/.virtualenvs/elpy-rpc-venv/bin/python3)
 Jedi.............: 0.16.0
 Rope.............: 0.16.0
 Autopep8.........: 1.5
 Yapf.............: 0.29.0
 Black............: 19.10b0
Syntax checker....: flake8 (/usr/bin/flake8)

so it runs the right jupyter from myvenv, but presumably using the python3 kernel from the main environment as the sys.path shown is not from myvenv. Same thing occurs in a terminal outside Emacs.

I thought I could get around the problem by creating a kernel with the same as the virtualenv; i.e. create a kernel named myvenv in the example above. Then, use pyvenv-post-activate-hooks and pyvenv-post-deactivate-hooks to set python-shell-interpreter-args to call the appropriate kernel:

(defun sl/pyvenv-toggle-python-shell-interpreter-args ()
  "toggle `python-shell-interpreter-args'"
  (setq python-shell-interpreter-args
	(format "console --kernel %s --simple-prompt"
		(or pyvenv-virtual-env-name "python3"))))
(add-hook 'pyvenv-post-activate-hooks
	  'sl/pyvenv-toggle-python-shell-interpreter-args)
(add-hook 'pyvenv-post-deactivate-hooks
	  'sl/pyvenv-toggle-python-shell-interpreter-args)

The post-activate hook works as expected, but not the post-deactivate hook, perhaps as per its docstring note: "‘`pyvenv-virtual-env’ is still set."

Any tips or alternative solutions?