Hello,

I’m quite new to PyMC and am trying out the GLM minibatch tutorial on PyMC v4.

The approximation is fitted without any issues. But sampling the approximation to arviz causes an error.

The line that causes the error:

```
idata_advi = az.from_pymc3(approx.sample(2000))
```

error trace:

```
---------------------------------------------------------------------------
ModuleNotFoundError Traceback (most recent call last)
/tmp/ipykernel_2197406/717053261.py in <module>
69 # run ADVI with minibatch
70 approx = pm.fit(100000, callbacks=[pm.callbacks.CheckParametersConvergence(tolerance=1e-4)])
---> 71 idata_advi = az.from_pymc3(approx.sample(2000))
~/.local/lib/python3.8/site-packages/arviz/data/io_pymc3_3x.py in from_pymc3(trace, prior, posterior_predictive, log_likelihood, coords, dims, model, save_warmup, density_dist_obs)
578 InferenceData
579 """
--> 580 return PyMC3Converter(
581 trace=trace,
582 prior=prior,
~/.local/lib/python3.8/site-packages/arviz/data/io_pymc3_3x.py in __init__(self, trace, prior, posterior_predictive, log_likelihood, predictions, coords, dims, model, save_warmup, density_dist_obs)
73 density_dist_obs: bool = True,
74 ):
---> 75 import pymc3
76
77 try:
ModuleNotFoundError: No module named 'pymc3'
```

From what I understand, it is because arviz is trying to use pymc3 instead of v4.

Is this tutorial outdated? or does something require a fix?