DOC: pymc.CustomDist example does not work in the documentation

Issue with current documentation:

When trying to run the following example code from the PYMC.CustomDist documentation, I get the error message "Core implementation of CustomDist_custom_dist_rv{"()->()"} not implemented":

from typing import Optional, Tuple

import numpy as np
import pymc as pm
from pytensor.tensor import TensorVariable

def logp(value: TensorVariable, mu: TensorVariable) -> TensorVariable:
    return -(value - mu)**2

def random(
    mu: np.ndarray | float,
    rng: Optional[np.random.Generator] = None,
    size : Optional[Tuple[int]]=None,
) -> np.ndarray | float :
    return rng.normal(loc=mu, scale=1, size=size)

with pm.Model():
    mu = pm.Normal('mu', 0 , 1)
    pm.CustomDist(
        'custom_dist',
        mu,
        logp=logp,
        random=random,
        signature="()->()",
        observed=np.random.randn(100, 3),
        size=(100, 3),
    )
    prior = pm.sample_prior_predictive(10)

Idea or request for content:

I do not know enough about PYMC to determine if this is a bug, my leaving something out, or the code not being correctly written in the documentation. If it is a bug, I will gladly report it as such. If if is not, please let me know what the correction is.

Start from the CustomDist documentation example shown in the issue and run it to reproduce the CustomDist_custom_dist_rv error. Check the documented CustomDist API and example context to determine whether the snippet is incomplete or incorrect; done when the published example runs successfully or clearly documents the required correction.