AssertEqual(t, false, ok)

	// null -> null
	err = DB.Table("unique_tests").AutoMigrate(&UniqueTest2{})
	if err != nil {
		t.Fatalf("AutoMigrate err:%v", err)
	}

	// not trigger alert column
	AssertEqual(t, true, DB.Migrator().HasConstraint(&UniqueTest{}, "uni_unique_tests_name"))
	AssertEqual(t, false, DB.Migrator().HasIndex(&UniqueTest{}, "name"))

 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#multimaps">{@code
 * Multimaps}</a>.
 *
 * @author Jared Levy
 * @author Robert Konigsberg
 * @author Mike Bostock
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Multimaps {
  private Multimaps() {}