func imag(c ComplexType) FloatType

// The clear built-in function clears maps and slices.
// For maps, clear deletes all entries, resulting in an empty map.
// For slices, clear sets all elements up to the length of the slice
// to the zero value of the respective element type. If the argument
// type is a type parameter, the type parameter's type set must
// contain only map or slice types, and clear performs the operation

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class CollectionClearTester<E> extends AbstractCollectionTester<E> {
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testClear() {
    collection.clear();
    assertTrue("After clear(), a collection should be empty.", collection.isEmpty());
    assertEquals(0, collection.size());
    assertFalse(collection.iterator().hasNext());
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)

    /**
     * Process an url when it's added as a seed url.
     *
     * @param url URL
     */
    void processUrl(String url);

    /**
     * Clear this filter.
     */
    void clear();

	// Clear
	if err := DB.Model(&user2).Association("Company").Clear(); err != nil {
		t.Errorf("Error happened when clear Company, got %v", err)
	}

	if err := DB.Model(&user2).Association("Manager").Clear(); err != nil {
		t.Errorf("Error happened when clear Manager, got %v", err)
	}

	AssertAssociationCount(t, user2, "Company", 0, "after clear")

    return (row == null) ? null : safeGet(row, columnKey);
  }

  @Override
  public boolean isEmpty() {
    return size() == 0;
  }

  @Override
  public void clear() {
    Iterators.clear(cellSet().iterator());
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable V remove(@Nullable Object rowKey, @Nullable Object columnKey) {
    Map<C, V> row = safeGet(rowMap(), rowKey);

    }

    public void mymodifyPropertyCancel(String propertyName) {
        __modifiedProperties.remove(propertyName);
    }

    public void clearModifiedInfo() {
        __modifiedProperties.clear();
    }

    public boolean hasModification() {
        return !__modifiedProperties.isEmpty();
    }

    protected EntityModifiedProperties newModifiedProperties() {

    }

    public void mymodifyPropertyCancel(String propertyName) {
        __modifiedProperties.remove(propertyName);
    }

    public void clearModifiedInfo() {
        __modifiedProperties.clear();
    }

    public boolean hasModification() {
        return !__modifiedProperties.isEmpty();
    }

    protected EntityModifiedProperties newModifiedProperties() {

			appendToRelations(reflectValue.Index(i), reflect.Indirect(reflect.ValueOf(values[i])), clear)
			if association.Error != nil {
				return
			}

			// TODO support save slice data, sql with case?
			association.Error = associationDB.Updates(reflectValue.Index(i).Addr().Interface()).Error
		}
	case reflect.Struct:
		// clear old data
		if clear && len(values) == 0 {

	}

	DB.Model(&hamster).Association("PreferredToy").Clear()

	if DB.Model(&hamster2).Association("PreferredToy").Count() != 0 {
		t.Errorf("Hamster's preferred toy should be cleared with Clear")
	}

	if DB.Model(&hamster2).Association("OtherToy").Count() != 1 {
		t.Errorf("Hamster's other toy should be still available")
	}

	DB.Model(&hamster).Association("OtherToy").Clear()

    public void test_DocList() {
        Map<String, Object> value = new LinkedHashMap<>();
        DocMap docMap = new DocMap(value);
        assertTrue(docMap.isEmpty());
        value.clear();

        List<String> keys = Arrays.asList("test_2", "test_0", "lang", "test_1");
        value.put(keys.get(0), true);
        value.put(keys.get(1), 1000);
        value.put(keys.get(2), "ja");