This week and next week (w/c 25/11/19) we will be making changes to scripts in the script repository to ensure python 2 & 3 compatibility. For the most part this was an automatic process using the 2to3.py script that is distributed with most python distributions (e.g.anaconda). We have reviewed all changes made but there may still be errors. If there are any issues, please let us know and we can either fix them, or if it is urgent, restore the old versions of the scripts (all previous versions of the scripts are publicly available on the GitHub repository GitHub - mantidproject/scriptrepository: This is the repository used for the user scripts repository in Mantid).
For most scripts there were only minor changes - the most common being adding brackets to print statements and adding from __future__ import print_function if necessary for compatibility with python 2. If there any problems with the updated scripts, the print statements are a good place to start looking.
Other common changes relate to functions such as range(), dict.keys() that return generators not lists in python 3 (similar to xrange in python 2.x) - the output from such functions has been explicitly converted to a list.
For more detail on the main changes form python 2 to 3 visit
https://python-future.org/compatible_idioms.html