Try setting the Lib file path
By default the script is taking /usr/lib path.
Check if that lib file is installed under /usr/lib or /opt/splunk/lib/ or any other path?
Either the lib file needs to be installed under default path /usr/lib or the LIB path needs to be set as below
NOTE: This will change lib path temporarily but in order to change it for permanent you need to add the line under .bashrc file of user with which the pythin script will get executed.
Hope this helps.