[externally-managed]
Error=This Python installation is managed by pkg_add(1).

 To install Python packages system-wide, use the OS packages where
 possible, for example: "pkg_add py3-somepackage".

 Otherwise, for software which is not available in packages,
 it is recommended to create a "venv" (virtual environment, see
 https://docs.python.org/3/library/venv.html) and install it there.
 For standalone applications, pipx (in the py3-pipx package) can
 help manage this for you.