How to use the posterior distribution of one model as a prior distribution for another model

@Simon @jessegrabowski @iavicenna

Thank you for your quick response. All the content is very informative!!

@jessegrabowski
I found an example of using histogram_approximation in a previous thread.
What is the difference between histogram_approximation and a multivariate normal approximation?
Would I use histogram_approximation to approximate a discrete distribution?