* referencing the type variables seem worthwhile.
   */
  final void checkNoDuplicate(R rowKey, C columnKey, @Nullable V existingValue, V newValue) {
    checkArgument(
        existingValue == null,
        "Duplicate key: (row=%s, column=%s), values: [%s, %s].",
        rowKey,
        columnKey,
        newValue,
        existingValue);
  }

  // redeclare to satisfy our test for b/310253115
  @Override

                                <c:if test="${editable}"><la:link styleClass="btn btn-info"
                                                                  href="/admin/webconfig/duplicate/${f:u(id)}">
                                    <i class="fa fa-copy" aria-hidden="true"></i>
                                    <la:message key="labels.crud_button_duplicate"/>
                                </la:link></c:if>

        for (Field field : fields) {
            if (field.getType() == int.class) {
                int value = field.getInt(null);
                assertTrue(values.add(value), "Duplicate value found for field: " + field.getName());
            }
        }
    }

    @Test
    @DisplayName("Test constant values follow bit flag pattern")
    void testConstantsBitFlagPattern() {

    checkNotNull(mergeFunction, "mergeFunction");

    /*
     * No mutable Table exactly matches the insertion order behavior of ImmutableTable.Builder, but
     * the Builder can't efficiently support merging of duplicate values.  Getting around this
     * requires some work.
     */

    return Collector.of(
        ImmutableTableCollectorState<R, C, V>::new,
        (state, input) ->
            state.put(

        // Test unregistration
        assertTrue(mockService.unregisterWitness(regId));
        assertEquals(0, mockService.getRegistrationCount());
        assertFalse(mockService.hasRegistration(regId));

        // Test duplicate unregistration
        assertFalse(mockService.unregisterWitness(regId));
    }

    @Test
    void testMockServiceNotifications() {
        // Test notification sending (just logs for mock)

 *
 * <p>When iterating through the collections supplied by this class, the ordering of values for a
 * given key agrees with the order in which the values were added.
 *
 * <p>This multimap allows duplicate key-value pairs. After adding a new key-value pair equal to an
 * existing key-value pair, the {@code ArrayListMultimap} will contain entries for both the new
 * value and the old value.
 *

    @SuppressWarnings("unchecked")
    E[] array = (E[]) elements.toArray();
    /*
     * For a Set, we guess that it contains no duplicates. That's just a guess for purpose of
     * sizing; if the Set uses different equality semantics, it might contain duplicates according
     * to equals(), and we will deduplicate those properly, albeit at some cost in allocations.
     */
    int expectedSize =

    }

    @Override
    public Set<E> create(Object... elements) {
      Object[] duplicated = new Object[elements.length * 2];
      for (int i = 0; i < elements.length; i++) {
        duplicated[i] = elements[i];
        duplicated[i + elements.length] = elements[i];
      }
      return ((Multiset<E>) gen.create(duplicated)).elementSet();
    }

    @Override
    public E[] createArray(int length) {

import java.util.Collection;
import java.util.Map;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link Multimap} using hash tables.
 *
 * <p>The multimap does not store duplicate key-value pairs. Adding a new key-value pair equal to an
 * existing key-value pair has no effect.
 *
 * <p>Keys and values may be null. All optional multimap methods are supported, and all returned
 * views are modifiable.

          else -> readToken()
        } ?: return // Expected a value.

      val replaced = parameters.put(peek, parameterValue)
      peek = null
      if (replaced != null) return // Unexpected duplicate parameter.
      if (!skipCommasAndWhitespace() && !exhausted()) return // Expected ',' or EOF.
    }
    result.add(Challenge(schemeName, parameters))
  }
}

/** Returns true if any commas were skipped. */