Rank-order rules

https://www.constituteproject.org/constitution/Burundi_2018?lang=en 2018 constution 

”The elections of deputies occur following the ballot of bloc lists by proportional representation. These lists must have a multiethnic character and take into account the balance between men and women. For three candidates registered on a list, only two can belong to the same ethnic group, and at least one of three must be a woman” (Article 173).