#simple-imputer

What does this print?

import numpy as np
from sklearn.impute import SimpleImputer

train = np.array([[22.0], [38.0], [np.nan], [26.0], [35.0]])   # ages
test = np.array([[np.nan], [50.0]])

imputer = SimpleImputer(strategy="median").fit(train)
print(imputer.transform(test)[0, 0])