code: def logpdf(self, mu):
          
          if self.transform is not None:
              mu = self.transform(mu)     
          return -np.log(float(self.sigma0)) - (0.5*(mu-self.mu0)**2)/float(self.sigma0**2)
docs: Log PDF for Normal prior
  
          Parameters
          ----------
          mu : float
              Latent variable for which the prior is being formed over
  
          Returns
          ----------
          - log(p(mu))