Prove an output is produced by a certain program which includes random methods

I am working on an NLP project through Python that creates some arbitrary quotes from given corpus. Since output is produced randomly, I want to make sure other people given output is generated by my program. I can use a package or other method within or without Python. It might be hard problem to prove it in a literal manner, just guessing, so a method that works for +95% is also welcome.

I think, I have some trouble with terminology, hints about how to search for this are also welcome!