human
Solve the following python programming problem given the following code:
# Any model should inherite hb.model.Model
class GPR(hb.model.Model):
    def setUp(self):
        """ 
        Set up parameters and Data for this model.
        Model.setUp is immediately called after Model.__init__()
        """
        # Data should be stored in hb.param.Data class. 
        self.X = hb.param.Data(X)
        self.Y = hb.param.Data(Y)
        
        # Variational parameters. 
        # By default, the shape of the variational covariance is 'diagonal'.
        # In small problems, the fullrank covariance can be inferred.
        self.q = hb.variationals.Gaussian(shape=X.shape, q_shape='fullrank')
        
        # Kernel object for GPR. 
        self.kern = hb.gp.kernels.UnitRBF()
        # Since our kernel does not contain the variance term, 
        # we should multiply positive parameter by hand.
        # To constrain k_var to stay in positive space, set transform option.
        self.k_var = hb.param.Variable(shape=[1], transform=hb.transforms.positive)
        
        # likelihood variance, which is also positive parameter.
        self.var = hb.param.Variable(shape=[1], transform=hb.transforms.positive)
        
    @hb.model.AutoOptimize()
    def ELBO_gaussian(self):
        """
        Any method decorated by @AutoOptimize can be optimized.
        In the decorated method, [hb.param.Variable, hb.variationals.Variational, 
        hb.param.Data] objects are treated as tf.Tensor.
        Therefore, tensorflow's method can be directoly used.
        
        Here, we calculate ELBO that should be maximized.
        """
        y_fit = tf.matmul(self.kern.Cholesky(self.X), self.q) * tf.sqrt(self.k_var)
        
        # Kulback-Leibler divergence can be accessed by self.KL() method.
        return tf.reduce_sum(hb.densities.gaussian(self.Y, y_fit, self.var))\
                - self.KL()
        
    @hb.model.AutoOptimize()
    def ELBO_student(self):
        """
        It is often convenient to prepare several variants of target method.
        In this method, we assume...
Given the above code, generate some markdown instructions for it.
assistant
#Here is Python program to calculate ELBO that should be maximized.

Construct a Henbun model