}

  @CanIgnoreReturnValue
  @Override
  public @Nullable V remove(@Nullable Object rowKey, @Nullable Object columnKey) {
    Map<C, V> row = safeGet(rowMap(), rowKey);
    return (row == null) ? null : Maps.safeRemove(row, columnKey);
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable V put(
      @ParametricNullness R rowKey, @ParametricNullness C columnKey, @ParametricNullness V value) {

    }
  }

  /**
   * Delegates to {@link Collection#remove}. Returns {@code false} if the {@code remove} method
   * throws a {@code ClassCastException} or {@code NullPointerException}.
   */
  static boolean safeRemove(Collection<?> collection, @Nullable Object object) {
    checkNotNull(collection);
    try {
      return collection.remove(object);
    } catch (ClassCastException | NullPointerException e) {
      return false;

    }

    @Override
    public @Nullable V remove(@Nullable Object key) {
      updateBackingRowMapField();
      if (backingRowMap == null) {
        return null;
      }
      V result = Maps.safeRemove(backingRowMap, key);
      maintainEmptyInvariant();
      return result;
    }

    @Override
    public void clear() {
      updateBackingRowMapField();
      if (backingRowMap != null) {

    }
  }

  /**
   * Delegates to {@link Map#remove}. Returns {@code null} on {@code ClassCastException} and {@code
   * NullPointerException}.
   */
  static <V extends @Nullable Object> @Nullable V safeRemove(Map<?, V> map, @Nullable Object key) {
    checkNotNull(map);
    try {
      return map.remove(key);
    } catch (ClassCastException | NullPointerException e) {
      return null;
    }
  }

    }
  }

  /**
   * Delegates to {@link Map#remove}. Returns {@code null} on {@code ClassCastException} and {@code
   * NullPointerException}.
   */
  static <V extends @Nullable Object> @Nullable V safeRemove(Map<?, V> map, @Nullable Object key) {
    checkNotNull(map);
    try {
      return map.remove(key);
    } catch (ClassCastException | NullPointerException e) {
      return null;
    }
  }