Hi, I’m struggling to tag a set of features with an ID, input data looks like the left case in this image:

What I want is shown on the right. My input has a line of data with the ID, and it’s implied each record after that has that ID, until a record resets the ID for the subsequent features.
Here’s a very similar example but differs from mine in that my ID is on a separate line:
It seems like a Python caller might work, but I’m not very handy with Python & FME. Any suggestions welcome. Thanks in advance!