Bug: Error Visualizing DecisionTreeRegressor

[reidjohnson]

Attempting to visualize the skops file for a sklearn DecisionTreeRegressor produces the following error:

TypeError: Cannot deal with <class 'type'>, please report the issue here: https://github.com/skops-dev/skops/issues

Reproducible example:

from sklearn.datasets import make_regression
from sklearn.tree import DecisionTreeRegressor
from sklearn.model_selection import train_test_split
from skops.io import dumps, loads, visualize

X, y = make_regression()
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.4)

dumped = dumps(DecisionTreeRegressor().fit(X_train, y_train))
loaded = loads(dumped)

visualize(dumped)