Creation of little python script

Hi, I need a little python script 2.7. We have such xml files (please see example: https://hidrive.ionos.com/lnk/eqGglL5C ) and only want to "search" and "replace" some words in the xml file. For example search for "eclass" and replace to "UNSPSC". Could you please make such a script for us?

Sometimes the xml files have a size of 500 MB, if that matters for you.