An example of solving something with another layer of indirection. https://en.wikipedia.org/wiki/Fundamental_theorem_of_software_engineering
createFunction(object, test_data)
The object that implements createFunction, e.g. heuristicsProb(ttb).
The test data that row_pairs will be drawn from. We recommend
A function that can easily be used by rowPairApply. This is not normally used by ordinary users.