You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: yamlh.go
    path of file: ./repos/delve/vendor/gopkg.in/yaml.v2
    
    the code of the file until where you have to start completion: package yaml

import (
	"fmt"
	"io"
)

// The version directive data.
type yaml_version_directive_t struc
    
func (tt yaml_token_type_t) String() string {
	switch tt {
	case yaml_NO_TOKEN:
		return "yaml_NO_TOKEN"
	case yaml_STREAM_START_TOKEN:
		return "yaml_STREAM_START_TOKEN"
	case yaml_STREAM_END_TOKEN:
		return "yaml_STREAM_END_TOKEN"
	case yaml_VERSION_DIRECTIVE_TOKEN:
		return "yaml_VERSION_DIRECTIVE_TOKEN"
	case yaml_TAG_DIRECTIVE_TOKEN:
		return "yaml_TAG_DIRECTIVE_TOKEN"
	case yaml_DOCUMENT_START_TOKEN:
		return "yaml_DOCUMENT_START_TOKEN"
	case yaml_DOCUMENT_END_TOKEN:
		return "yaml_DOCUMENT_END_TOKEN"
	case yaml_BLOCK_SEQUENCE_START_TOKEN:
		return "yaml_BLOCK_SEQUENCE_START_TOKEN"
	case yaml_BLOCK_MAPPING_START_TOKEN:
		return "yaml_BLOCK_MAPPING_START_TOKEN"
	case yaml_BLOCK_END_TOKEN:
		return "yaml_BLOCK_END_TOKEN"
	case yaml_FLOW_SEQUENCE_START_TOKEN:
		return "yaml_FLOW_SEQUENCE_START_TOKEN"
	case yaml_FLOW_SEQUENCE_END_TOKEN:
		return "yaml_FLOW_SEQUENCE_END_TOKEN"
	case yaml_FLOW_MAPPING_START_TOKEN:
		return "yaml_FLOW_MAPPING_START_TOKEN"
	case yaml_FLOW_MAPPING_END_TOKEN:
		return "yaml_FLOW_MAPPING_END_TOKEN"
	case yaml_BLOCK_ENTRY_TOKEN:
		return "yaml_BLOCK_ENTRY_TOKEN"
	case yaml_FLOW_ENTRY_TOKEN:
		return "yaml_FLOW_ENTRY_TOKEN"
	case yaml_KEY_TOKEN:
		return "yaml_KEY_TOKEN"
	case yaml_VALUE_TOKEN:
		return "yaml_VALUE_TOKEN"
	case yaml_ALIAS_TOKEN:
		return "yaml_ALIAS_TOKEN"
	case yaml_ANCHOR_TOKEN:
		return "yaml_ANCHOR_TOKEN"
	case yaml_TAG_TOKEN:
		return "yaml_TAG_TOKEN"
	case yaml_SCALAR_TOKEN:
		return "yaml_SCALAR_TOKEN"
	}
	return "<unknown token>"
}