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: group.rb
    path of file: ./repos/chef/lib/chef/provider
    
    the code of the file until where you have to start completion: #
# Author:: AJ Christensen (<aj@chef.io>)
# Copyright:: Copyright (c) Chef Software Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not u
    
      def validate_member!(member)
        # Sub-classes can do any validation if needed
        # and raise an error if validation fails
        true
      end

      action :create do
        case @group_exists
        when false
          converge_by("create group #{new_resource.group_name}") do
            create_group
            logger.info("#{new_resource} created")
          end
        else
          if compare_group
            converge_by(["alter group #{new_resource.group_name}"] + change_desc) do
              manage_group
              logger.info("#{new_resource} altered: #{change_desc.join(", ")}")
            end
          end
        end