### Validation

* Validation for most (or all?) Python **data types**, including:
    * JSON objects (`dict`).
    * JSON array (`list`) defining item types.
    * String (`str`) fields, defining min and max lengths.
    * Numbers (`int`, `float`) with min and max values, etc.

* Validation for more exotic types, like:
    * URL.
    * Email.
    * UUID.
    * ...and others.

 *
 * @author Pete Gillin
 * @since 20.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class PairedStatsAccumulator {

  // These fields must satisfy the requirements of PairedStats' constructor as well as those of the
  // stat methods of this class.
  private final StatsAccumulator xStats = new StatsAccumulator();

    }

    @Override
    public void init() throws IOException {
        // nothing
    }

    @Override
    public List<String> convert(final String text, final String field, final String... lang) {
        final List<String> list = new ArrayList<>();

        final List<StringBuilder> bufList = new ArrayList<>();
        bufList.add(new StringBuilder());

      metadata.is_list = 1;
      metadata.list_size = 0;
      metadata.total_size = -1;
#define LIST_CASE(field, attr_type, ...)              \
  if (attr->list().field##_size() > 0) {              \
    metadata.type = attr_type;                        \
    metadata.list_size = attr->list().field##_size(); \
    __VA_ARGS__;                                      \
    break;                                            \

	return k[:], err
}

// ParseSSECustomerRequest parses the SSE-C header fields of the provided request.
// It returns the client provided key on success.
func ParseSSECustomerRequest(r *http.Request) (key []byte, err error) {
	return ParseSSECustomerHeader(r.Header)
}

// ParseSSECustomerHeader parses the SSE-C header fields and returns
// the client provided key on success.

///

/// tip | "Tipp"

///

## Type Hints với Metadata Annotations

Python cũng có một tính năng cho phép đặt **metadata bổ sung** trong những gợi ý kiểu dữ liệu này bằng cách sử dụng `Annotated`.

    static final int IN = 0x0001;
    static final int A = 0x0001;
    static final int NS = 0x0002;
    static final int NULL = 0x000a;

    static final int HEADER_LENGTH = 12;

    // header field offsets
    static final int OPCODE_OFFSET = 2;
    static final int QUESTION_OFFSET = 4;
    static final int ANSWER_OFFSET = 6;
    static final int AUTHORITY_OFFSET = 8;
    static final int ADDITIONAL_OFFSET = 10;

    static final int A         = 0x0001;
    static final int NS        = 0x0002;
    static final int NULL      = 0x000a;

    static final int HEADER_LENGTH = 12;

    // header field offsets
    static final int OPCODE_OFFSET = 2;
    static final int QUESTION_OFFSET = 4;
    static final int ANSWER_OFFSET = 6;
    static final int AUTHORITY_OFFSET = 8;
    static final int ADDITIONAL_OFFSET = 10;

			return err
		}
	} else {
		// Evaluate the (only) argument
		val, err = e.SFunc.ArgsList[0].evalNode(r, tableAlias)
		if err != nil {
			return err
		}
	}

	if val.IsNull() {
		// E.g. the column or field does not exist in the
		// record - in all such cases the aggregation is not
		// updated.
		return nil
	}

	argVal := val
	if funcName != aggFnCount {
		// All aggregation functions, except COUNT require a