I am trying to construct a Bayesian neural network model for regression problem by referring to the example in the doc http://docs.pymc.io/notebooks/bayesian_neural_network_advi.html

The model looks like this

sampling result

Then I try to do something similar to the doc example, I guess there are two ways to write the function

The first way shows

Then I am a bit confused with the part, how to construct the part of prediction with the posteriorâ€¦

Thanks a lot in advance.