Fix outdated Model docstring (#6048)

Author: alekracicot

pymc/model.py

@@ -465,15 +465,15 @@ def __init__(self, mean=0, sigma=1, name=''):
                 # variables in several ways note, that all variables
                 # will get model's name prefix
 
-                # 3) you can create variables with Var method
-                self.Var('v1', Normal.dist(mu=mean, sigma=sd))
-                # this will create variable named like '{prefix::}v1'
+                # 3) you can create variables with the register_rv method
+                self.register_rv(Normal.dist(mu=mean, sigma=sigma), 'v1', initval=1)
+                # this will create variable named like '{name::}v1'
                 # and assign attribute 'v1' to instance created
                 # variable can be accessed with self.v1 or self['v1']
 
                 # 4) this syntax will also work as we are in the
                 # context of instance itself, names are given as usual
-                Normal('v2', mu=mean, sigma=sd)
+                Normal('v2', mu=mean, sigma=sigma)
 
                 # something more complex is allowed, too
                 half_cauchy = HalfCauchy('sigma', beta=10, initval=1.)
@@ -510,7 +510,6 @@ def __init__(self, mean=0, sigma=1, name=''):
             CustomModel(mean=2, name='second')
 
         # variables inside both scopes will be named like `first::*`, `second::*`
-
     """
 
     if TYPE_CHECKING: