Google App Script functions to fetch data from Klaviyo APIs as covered in https://developers.klaviyo.com/en/reference/api_overview.
"The Klaviyo API is very awkwardly designed for reporting, as nearly every request involves first pulling IDs, then running a second (or third...) request to associate those IDs with metrics" (https://mixedanalytics.com/knowledge-base/import-klaviyo-data-to-google-sheets)
The functions in this repo are an effort to get the needed data through that design.