how change max depth of tree in clf python code example

Example: scikit decision tree classifier gini criterion

from sklearn.tree import DecisionTreeClassifier
from sklearn import metrics

# Max depth Decision tree classifier using gini criterion 

clf_gini_max = DecisionTreeClassifier(random_state=50, criterion='gini', max_depth=None)

clf_gini_max = clf_gini_max.fit(X_train,Y_train)
Y_pred = clf_gini_max.predict(X_test)

training_accuracy = clf_gini_max.score(X_train,Y_train)
testing_accuracy = clf_gini_max.score(X_test,Y_test)

print(training_accuracy)
print(testing_accuracy)