aweber/AWeber-API-Ruby-Library — pull request #30 by bemurphy (2014-06-23 15:30:43+00:00)
Title: Add the List#unique_list_id per changelog

https://labs.aweber.com/docs/reference/1.0#list_entry now shows
the unique list id. This is useful for building forms out of data
from API calls.

This attribute entered at API version 1.0.21 per the changlog at
https://labs.aweber.com/docs/changelog