First revision: 20/07/2023

v0.1: first version, just creates a new column "variants" and assigns the correct variant name to each row.

v0.2: outputs the aggregated results as required.

v0.3: more modern, good-looking UI.

v0.4: count only unique events per user: only 1 event will count for each encoded_recipient_id per campaign_id, delivery_id, var_code, event_type. Filename is now the original filename + _processed.

v0.5: order variants alphabetically in final report but keep DEF variants before D variants.