Fix HSGP docstrings examples

Author: ricardoV94

pymc/gp/hsgp_approx.py

@@ -446,7 +446,7 @@ class HSGPPeriodic(Base):
 
         with pm.Model() as model:
             # Specify the covariance function, only for the 1-D case
-            scale = pm.HalfNormal(10)
+            scale = pm.HalfNormal("scale", 10)
             cov_func = pm.gp.cov.Periodic(1, period=1, ls=0.1)
 
             # Specify the approximation with 25 basis vectors
@@ -535,8 +535,8 @@ def prior_linearized(self, Xs: TensorLike):
             X = np.linspace(0, 10, 100)[:, None]
 
             with pm.Model() as model:
-                scale = pm.HalfNormal(10)
-                cov_func = pm.gp.cov.Periodic(1, period=1, ls=ell)
+                scale = pm.HalfNormal("scale", 10)
+                cov_func = pm.gp.cov.Periodic(1, period=1.0, ls=2.0)
 
                 # m=200 means 200 basis vectors
                 gp = pm.gp.HSGPPeriodic(m=200, scale=scale, cov_func=cov_func)