Issue with nagios plugin check_mongodb.py", line 409 with python3.8

Hi, I recently changed the python version to version 3.8. Then I got this error:
(No output on stdout) stderr: File "/etc/nagios-plugins/nagios-plugin-mongodb/check_mongodb_modified.py", line 409 

All the checks started producing that error. 

When switched /usr/bin/python back to python 2.7 the checks started working again. Any reason why this is? 