class Lutaml::Model::KeyValueTransform

def rule_value_for(name, doc, rule, format, attr)
  if rule.root_mapping?
    doc
  elsif rule.raw_mapping?
    convert_to_format(doc, format)
  elsif Utils.string_or_symbol_key?(doc, name)
    Utils.fetch_with_string_or_symbol_key(doc, name)
  elsif attr&.default_set?
    attr.default
  else
    Lutaml::Model::UninitializedClass.instance
  end
end