import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An immutable builder for {@link Multimap} instances, letting you independently select the desired
 * behaviors (for example, ordering) of the backing map and value-collections. Example:
 *
 * <pre>{@code
 * ListMultimap<UserId, ErrorResponse> errorsByUser =