Puppet Apply调用Deferred函数报错：未知函数mymodule::myupcase

我按照Puppet官方文档测试Deferred函数，执行了以下步骤：

1. 创建目录结构并运行PDK命令：

cd ~/dev/src/local/puppet_tests
pdk new module mymodule
cd mymodule
pdk new class mymodule
mkdir -p lib/puppet/functions/mymodule

2. 在manifests/init.pp文件中写入代码：

class mymodule {
  $d = Deferred("mymodule::myupcase", ["mysecret"])

  notify { example :
    message => $d
  }
}

class { 'mymodule': }

3. 在lib/puppet/functions/mymodule/目录下创建myupcase.rb文件并写入代码：

Puppet::Functions.create_function(:'mymodule::myupcase') do
  dispatch :up do
    param 'String', :some_string
  end

  def up(some_string)
    Puppet::Pops::Types::PSensitiveType::Sensitive.new(some_string.upcase)
  end
end

4. 运行puppet apply manifests/init.pp命令时出现错误：

~/dev/src/local/puppet_tests/mymodule main*
❯ puppet apply manifests/init.pp
Notice: Compiled catalog for localhost.localdomain in environment production in 0.04 seconds
Error: Unknown function 'mymodule::myupcase'

移除init.pp中引用$d变量的代码块后可正常运行，但这并非解决问题的方法。

我的环境信息：

• 操作系统：MacOS 13.4.1
• Puppet版本：8.1.0
• 通过brew安装puppet-agent和PDK：

brew install --cask puppetlabs/puppet/puppet-agent
brew install --cask puppetlabs/puppet/pdk

补充测试：改用pdk new function命令创建函数，错误仍然存在：

cd ~/dev/src/local/puppet_tests
pdk new module mymodule
cd mymodule
pdk new class mymodule
pdk new function myupcase --type=v4

该命令生成了spec目录及相关文件，最终的myupcase.rb代码如下：

# frozen_string_literal: true

# https://github.com/puppetlabs/puppet-specifications/blob/master/language/func-api.md#the-4x-api
Puppet::Functions.create_function(:"mymodule::myupcase") do
  dispatch :myupcase do
    param 'String', :a
    return_type 'String'
  end
  # the function below is called by puppet and and must match
  # the name of the puppet function above. You can set your
  # required parameters below and puppet will enforce these
  # so change x to suit your needs although only one parameter is required
  # as defined in the dispatch method.
  def myupcase(x)
    x.upcase
  end

  # you can define other helper methods in this code block as well
end

init.pp文件内容保持不变。请问我遗漏了什么？

内容的提问来源于stack exchange，提问作者Giuliani Sanches