import org.jspecify.annotations.Nullable;

/**
 * A series of tests that support asserting that collections cannot be modified, either through
 * direct or indirect means.
 *
 * @author Robert Konigsberg
 */
@GwtCompatible
@NullMarked
public class UnmodifiableCollectionTests {

  public static void assertMapEntryIsUnmodifiable(Entry<?, ?> entry) {
    try {

// reservations) 2008-07-01
de

// dj : https://www.iana.org/domains/root/db/dj.html
dj

// dk : https://www.iana.org/domains/root/db/dk.html
// Confirmed by registry <robert@dk-hostmaster.dk> 2008-06-17
dk

// dm : https://www.iana.org/domains/root/db/dm.html
// https://nic.dm/policies/pdf/DMRulesandGuidelines2024v1.pdf
// Confirmed by registry <******@****.***> 2024-11-19
dm
co.dm

 *
 * <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
public final class Multimaps {
  private Multimaps() {}

  /**