for (Table<Character, Integer, String> testInstance : getTestInstances()) {
      assertThrows(UnsupportedOperationException.class, () -> testInstance.remove('a', 1));
    }
  }

  public final void testConsistentToString() {
    for (ImmutableTable<Character, Integer, String> testInstance : getTestInstances()) {
      assertEquals(testInstance.rowMap().toString(), testInstance.toString());
    }
  }