Thanks, nruddock...  yes, that makes sense. It would be better for the script to check whether file compression is turned off or on in Preferences, and so read the appropriate file ( .mc6 or .mcz ). But I don't know if that can be checked in Python.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)