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: builder.rb
    path of file: ./repos/simple_form/lib/simple_form/action_view_extensions
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
module SimpleForm
  module ActionViewExtensions
    #
    
      def simple_fields_for(*args, &block)
        options = args.extract_options!
        options[:wrapper] = self.options[:wrapper] if options[:wrapper].nil?
        options[:defaults] ||= self.options[:defaults]
        options[:wrapper_mappings] ||= self.options[:wrapper_mappings]

        if self.class < ActionView::Helpers::FormBuilder
          options[:builder] ||= self.class
        else
          options[:builder] ||= SimpleForm::FormBuilder
        end