pynguin: TypeError: unsupported operand type(s) for |: 'NoneType' and 'NoneType'

Describe the bug Error when generating tests: TypeError: unsupported operand type(s) for |: 'NoneType' and 'NoneType'

To Reproduce Steps to reproduce the behaviour:

1. Use Pynguin version ‘0.34.0’
2. Use the following (minimal) code as a subject for test generation:

import os
import numpy as np
import pandas as pd
import matplotlib
import matplotlib.pyplot as plt


class FilterCorrelatedFeatures:

    def __init__(self, corr_threshold=0.80):
        self.corr_threshold = corr_threshold
        self.correlated_features = []
        self.corr_matrix = pd.DataFrame()

1. Use the following command line arguments to Pynguin: python -m pynguin --output-path . -v --project-path src/data_preprocessing/ --module-name hello

2. Give the error (stack trace, etc) you are encountering: ‘…’ pynguin-log.txt

Expected behavior generate a simple test.

Screenshots NA

Software Version (please complete the following information):

• OS: [Ubuntu 20.04.6 LTS]
• Python version [3.10.13]
• Pynguin Version [0.34.0]