Custom StatTest Failing in Python Due to missing Python Engine

[rygeorge3]

When attempting to implement a custom StatTest in python, the run function is failing with the following error:

• Test failed with exceptions: 'mann-whitney-u' is not implemented for <class 'evidently.calculation_engine.python_engine.PythonEngine'>

See below for the code to reproduce the error.

• The code was taken from this link: https://github.com/evidentlyai/evidently/blob/main/examples/how_to_questions/how_to_specify_stattest_for_a_testsuite.ipynb

import pandas as pd
import numpy as np

from scipy.stats import mannwhitneyu
from sklearn import datasets

from evidently.calculations.stattests import StatTest
from evidently.test_suite import TestSuite
from evidently.tests import *

#Dataset for Data Quality and Integrity
adult_data = datasets.fetch_openml(name='adult', version=2, as_frame='auto')
adult = adult_data.frame

adult_ref = adult[~adult.education.isin(['Some-college', 'HS-grad', 'Bachelors'])]
adult_cur = adult[adult.education.isin(['Some-college', 'HS-grad', 'Bachelors'])]

adult_cur.iloc[:2000, 3:5] = np.nan

def _mann_whitney_u(reference_data: pd.Series, current_data: pd.Series, _feature_type: str, threshold: float):
p_value = mannwhitneyu(np.array(reference_data), np.array(current_data))[1]
return p_value, p_value < threshold

mann_whitney_stat_test = StatTest(
name="mann-whitney-u",
display_name="mann-whitney-u test",
func=_mann_whitney_u,
allowed_feature_types=["num"]
)

data_drift_dataset_tests = TestSuite(tests=[
TestShareOfDriftedColumns(num_stattest=mann_whitney_stat_test),
])

data_drift_dataset_tests.run(reference_data=adult_ref, current_data=adult_cur)
data_drift_dataset_tests

[Nakulbajaj101]

I tried with 0.4.2 and it worked. On 0.4.7 there were some other issues, and 0.4.0 was missing some tests. They definitely stuffed something up with Python engine , and since they made func a property