You actually don't need to know any pvk Yourself but just for introduce You a specific method that You can understand or try at least, for a test purpose I needed to write everything like "we need" initial pvk to demonstrate but the cracking reality is simple : string from step6 + target address, no more details and I'll demonstrate how fast I am.
So I sat here the last 10 minutes to create my own script to do what you are doing.
I was successful.
Knowing the range speeds up the script, in that you can eliminate certain numbers, but the range is not needed.