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: test_coder.rb
    path of file: ./repos/truffleruby/test/mri/tests/psych
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
require_relative 'helper'

module Psych
  class TestCoder < TestCase
    class InitApi
      attr_accessor :implicit
      attr_acc
    
    def test_map_takes_block
      coder = Psych::Coder.new 'foo'
      tag = coder.tag
      style = coder.style
      coder.map { |map| map.add 'foo', 'bar' }
      assert_equal 'bar', coder['foo']
      assert_equal tag, coder.tag
      assert_equal style, coder.style
    end