import java.util.List;
public interface NestedInteger {
// @return true if this NestedInteger holds a single integer, rather than a nested list.
boolean isInteger();
// @return the single integer that this NestedInteger holds, if it holds a single integer
// Return null if this NestedInteger holds a nested list
Integer getInteger();
// @return the nested list that this NestedInteger holds, if it holds a nested list
// Return null if this NestedInteger holds a single integer
List getList();
}