premise: Viola Davis only plays lead roles.
hypothesis: Viola Davis . For her lead role as 1960s housemaid Aibeleen Clark in the comedy-drama The Help ( 2011 ) , she received a nomination for the Academy Award for Best Actress among others , and won a SAG Award . Since 2014 , Davis has played lawyer Annalise Keating in the ABC television drama , How to Get Away with Murder , and in 2015 she became the first black woman to win the Primetime Emmy Award for Outstanding Lead Actress in a Drama Series .