If written in a manner analogous to DiscreteProbability, the class SampleSpace defined in the last exercise is said to provide "random selection with replacement." The alternative, random selection without replacement, is frequently more useful. For example, a sample space might represent a deck of cards, and a random selection, the choosing of a card. This card should then be thought of as being removed from the deck and not available for return in subsequent selections. Describe how to modify the class SampleSpace to provide random selection without replacement.