You can draw a straight line from Ukrainian MP Serhiy Leshchenko to Ukrainian American Alexandra Chalupa an operative on the DNC payroll, who after checking in at the Ukrainian Embassy in DC was sent to Kiev to meet Leshchenko and dig up dirt on Paul Manafort.
If I had to guess I’d say the hand written ledger Leshchenko ‘found’ is a Ukrainian intelligence service fabrication.
Reconstructing the Russian Trump Dossier Story: A Timeline
Spring 2015: Hackers target DNC consultant Alexandra Chalupa, who was doing opposition research on Donald Trump; Chalupas emails will later be released by Wikileaks
Summer 2015: Hacker COZY BEAR infiltrates DNC network