Input DataFrame: rowsCount = 7, columnsCount = 5

name		age	city	weight	isHappy
firstName	lastName
Alice	Cooper	15	London	54	true
Bob	Dylan	45	Dubai	87	true
Charlie	Daniels	20	Moscow	null	false
Charlie	Chaplin	40	Milan	null	true
Bob	Marley	30	Tokyo	68	true
Alice	Wolf	20	null	55	false
Charlie	Byrd	30	Moscow	90	true

Output DataFrame: rowsCount = 7, columnsCount = 5

name		age	city	isHappy	weight
firstName	lastName
Alice	Cooper	15	London	true	54
Bob	Dylan	45	Dubai	true	87
Charlie	Daniels	20	Moscow	false	null
Charlie	Chaplin	40	Milan	true	null
Bob	Marley	30	Tokyo	true	68
Alice	Wolf	20	null	false	55
Charlie	Byrd	30	Moscow	true	90