public static SqlArray of(final SqlType itemType) {
    return new SqlArray(itemType);
  }
@SuppressWarnings("UnstableApiUsage")
  @Test
  public void shouldImplementHashCodeAndEqualsProperly() {
    new EqualsTester()
        .addEqualityGroup(SqlArray.of(SOME_TYPE), SqlArray.of(SOME_TYPE))
        .addEqualityGroup(SqlArray.of(SqlPrimitiveType.of(SqlBaseType.BOOLEAN)))
        .addEqualityGroup(SqlMap.of(SqlTypes.STRING, SqlTypes.BOOLEAN))
        .testEquals();
  }