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: mongo_crypt_spec_helper.rb
    path of file: ./repos/mongo-ruby-driver/spec/mongo/crypt/helpers
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
# rubocop:todo all

module MongoCryptSpecHelper
  def bind_crypto_hooks(mongocrypt)
    Mongo::Crypt::Binding.mongocrypt_setopt_crypto_hook
    
  def hmac_sha_256(_, key_binary_p, input_binary_p, output_binary_p, status_p)
    key = string_from_binary(key_binary_p)
    input = string_from_binary(input_binary_p)

    output = Mongo::Crypt::Hooks.hmac_sha('SHA256', key, input)
    write_to_binary(output_binary_p, output)

    true
  end