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: mutation.rb
    path of file: ./repos/souls/lib/souls/cli/update
    
    the code of the file until where you have to start completion: require_relative "../cli_exception"

module SOULs
  class Update < Thor
    desc "create_mutation [CLASS_NAME]", "Update GraphQL Type from schema.rb"
    def create_mutation(class_name)
      singularized_class_name = class_name.singularize.underscore
      new_cols = SOULs.get_columns_num(class_name: singularized_class_name)
      dir_name = "./app/graphql/mut
    
    def check_mutation_argument(class_name: "user", action: "action")
      singularized_class_name = class_name.singularize.underscore
      dir_name = "./app/graphql/mutations/base/#{singularized_class_name}"
      file_path = "#{dir_name}/#{action}_#{singularized_class_name}.rb"
      args = []
      File.open(file_path) do |f|
        f.each_line do |line|
          args << line.split(",")[0].gsub("argument :", "").strip.underscore if line.include?("argument")
        end
      end
      args
    end