white space in feature names don't work about dtreeviz HOT 4 CLOSED

from sklearn.datasets import *
from dtreeviz.trees import *
from IPython.display import Image, display_svg

# data from https://archive.ics.uci.edu/ml/datasets/User+Knowledge+Modeling
clf = tree.DecisionTreeClassifier(max_depth=3)
know = pd.read_csv("testing/data/knowledge.csv")
target_names = ['very_low', 'Low', 'Middle', 'High']
know['UN S'] = know['UNS'].copy()
know['P E G'] = know['PEG'].copy()
know = know.drop(['UNS','PEG'], axis=1)

know['UN S'] = know['UN S'].map({n: i for i, n in enumerate(target_names)})

X_train, y_train = know.drop('UN S', axis=1), know['UN S']
clf = clf.fit(X_train, y_train)

viz = dtreeviz(clf, 
               X_train,
               y_train,
               target_name='UN S',
               feature_names=X_train.columns.values,
               class_names=target_names,
               fancy=True)
viz