premise: Bethanie Mattek-Sands and Coco Vandeweghe were the defending champions, but chose not to participate together. Mattek-Sands played alongside Lucie Šafářová, but lost in the semifinals to Chan Yung-jan and Martina Hingis. Vandeweghe teamed up with Shelby Rogers, but lost in the first round to Andreja Klepač and María José Martínez Sánchez.
hypothesis: Bethanie Mattek-Sands and Coco Vandeweghe both had only one leg
reason: nothing in the statement necessitates that these two people both had two legs, the system assumes that they did