Cracking bcrypt hash using brute force mode

[Justonthis]

Pure masks don't support this but you can create a hcmask file with policygen from PACK: https://github.com/iphelix/PACK

Can I use pack to create a wordlist that fits my potential word candidates? then I use it later for wordlist attack and what's the command line for it please?
I got to work only by typing "python3" and not "python" is that okay? 
My rules are 
--minlength 4 --maxlength 4
Capital letters and non capital letters
One number max each word or no numbers at all