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_mime_type.rb
    path of file: ./repos/ruby-mime-types/test
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require "mime/types"
require "minitest_helper"

describe MIME::Type do
  def mime_type(content_type)
    MIME::Type.
    
    def assert_has_keys(wanted_keys, actual, msg = nil)
      wanted_keys = Array(wanted_keys).uniq.sort
      actual_keys = if actual.is_a?(Hash)
        actual.keys
      else
        actual.to_h.keys
      end