how to call function in different module?

Well I looked at it again on GIThub. I reviewed the license. And from my reading of it, it is OK for me to use. But it does seem strange that going to the OrgChartPro page shows https://www.orgchartpro.com/store/ for a considerable sum. Can anyone explain to me if this is free to use? Or are they two different products?

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proof that an old dog can learn new tricks