class Lutaml::Model::KeyValueTransform

def extract_rule_value(doc, rule, format, attr)
  rule_names = rule.multiple_mappings? ? rule.name : [rule.name]
  rule_names.each do |rule_name|
    value = rule_value_for(rule_name, doc, rule, format, attr)
    return value if Utils.initialized?(value)
  end
  Lutaml::Model::UninitializedClass.instance
end