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: parserc.go
    path of file: ./repos/ko/vendor/sigs.k8s.io/yaml/goyaml.v2
    
    the code of the file until where you have to start completion: package yaml

import (
	"bytes"
)

// The parser implements the following grammar:
//
// stream               ::= STREAM-START implicit_document? explicit_document* STREAM-END
// implicit_document    ::= block_node DOCUMENT-END*
// explicit_document    ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
// block_node_or_indentless_sequence    ::=
//                         
    
func yaml_parser_append_tag_directive(parser *yaml_parser_t, value yaml_tag_directive_t, allow_duplicates bool, mark yaml_mark_t) bool {
	for i := range parser.tag_directives {
		if bytes.Equal(value.handle, parser.tag_directives[i].handle) {
			if allow_duplicates {
				return true
			}
			return yaml_parser_set_parser_error(parser, "found duplicate %TAG directive", mark)
		}
	}

	// [Go] I suspect the copy is unnecessary. This was likely done
	// because there was no way to track ownership of the data.
	value_copy := yaml_tag_directive_t{
		handle: make([]byte, len(value.handle)),
		prefix: make([]byte, len(value.prefix)),
	}
	copy(value_copy.handle, value.handle)
	copy(value_copy.prefix, value.prefix)
	parser.tag_directives = append(parser.tag_directives, value_copy)
	return true
}