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: configuration.rb
    path of file: ./repos/identity-idp/lib/telephony
    
    the code of the file until where you have to start completion: require 'logger'

module Telephony
  class PinpointConfiguration
    attr_reader :sms_configs, :voice_configs

    def initialize
      @sms_configs = []
     
    
    def add_voice_config
      raise 'missing voice configuration block' unless block_given?
      voice = PinpointVoiceConfiguration.new(region: 'us-west-2')
      yield voice
      voice_configs << voice
      voice
    end