[mythtvnz] Python and tv_grab_nz-py for Ubuntu 20.04

[Stephen Worthington]

On Fri, 17 Jul 2020 09:00:55 +1200, you wrote:

>Nice work Stephen.
>
>You should be able to get around the multiple versions of python by using
>the #!/usr/bin/env python shebang instead.
>
>Cheers,
>
>Hadley

No such luck.  On my clean Xubuntu 20.04 virtual machine, there is no
"python" executable.  To get it, you have to install an extra package:

apt install python-is-python3

It would have been nice if that was installed by default.