Simple question: correct way to save traces?

Would someone mind providing code example for correct saving/loading model, trace as well as observed variables in order for it to be easily reinitialised and used for prediction?

If I pickle save pm.Model() object, are variables and structure going to be saved as well?
Will I i.e. be able to update priors (using from_posterior example) for online learning when new data is available?

Also, what would be the best way for me to have placeholder for predictors/observed variable in eg. logistic regression, to create python class BayesianLogisticRegression() without passing any data or even assumption on data shape?