(Initially raised in Stack Overflow question https://stackoverflow.com/questions/70403306/pyparsing-issue-with-3-0-works-with-2-4-pyparsing.)

When WordStart is defined with a value given for word_chars argument, either without the argument name "word_chars" or with the argument name "wordChars", the default printables value is used by mistake. This is due to a bug in the PEP-8 compatibility logic for detecting word_chars or wordChars arguments. (Also affects WordEnd.)