Place draining basket in pressure cooker. Rinse beans. Place them in basket, with all remaining ingredients except sherry. Cover cooker, lock lid and bring to pressure then cook 45 minutes. Lift basket and allow solids to drain. Remove pork knuckles. Puree remaining solids in two batches with metal blade of food processor. Return puree to stock and stir ro combine. Add sherry to taste. Cut meat from ham hocks into small pieces and add to soup. Serve with sourdough rolls. From "Cuisinart Quiet Pressure Cooker Recipes"