code: def pdf(self, mu):
          
          if self.transform is not None:
              mu = self.transform(mu)    
          return self.pdf_internal(mu, df=self.df0, loc=self.loc0, scale=self.scale0, gamma=self.gamma0)
docs: PDF for Skew t prior
  
          Parameters
          ----------
          mu : float
              Latent variable for which the prior is being formed over
  
          Returns
          ----------
          - p(mu)