What is the standard of review for an award of attorneys' fees?

The traditional standard of review of an award of attorneys' fees is highly deferential to the district court. Where, however, an appellant's contention on appeal regarding an award of attorneys' fees is that the district court made an error of law, "the district court's rulings of law are reviewed de novo." Baker v. Health Mgmt. Sys., Inc., 264 F.3d 144, 149 (2d Cir.2001).