Using pm.MvNormal for setting prior distribution

Questions
2 
import numpy as np
import pymc3 as pm
import theano.tensor as tt

with pm.Model() as model_a:
    x = pm.MvNormal('vals', mu=mu, cov=cov, shape=(1, 2))
    c, m = tt.split(x, [1, 1], n_splits=2, axis=1)
    deltmu = pm.Deterministic('deltmu', c*delta**m)
    deltmu = tt.squeeze(deltmu)
    y = pm.Normal('y', mu=deltmu[0], sd=0.1, observed=growth)
    trace_a = pm.sample(10000, cores=1)

Also, the sd parameter has been deprecated. Use sigma instead!