public static RelDataType create(HazelcastIntegerType type, boolean nullable) {
        if (type.isNullable() == nullable) {
            return type;
        }

        return create0(type.getSqlTypeName(), nullable, type.getBitWidth());
    }
@Test
    public void testNullableIntegerTypeOfType() {
        HazelcastIntegerType intType = HazelcastIntegerType.create(INTEGER, false);
        HazelcastIntegerType nullableIntType = HazelcastIntegerType.create(INTEGER, true);

        assertSame(intType, HazelcastIntegerType.create(intType, false));
        assertSame(nullableIntType, HazelcastIntegerType.create(intType, true));

        assertSame(intType, HazelcastIntegerType.create(nullableIntType, false));
        assertSame(nullableIntType, HazelcastIntegerType.create(nullableIntType, true));
    }