# File lib/adhearsion/voip/asterisk/config_generators/queues.conf.rb, line 229
            def sound_files(hash_of_files)
              hash_of_files.each_pair do |key, value|
                unless SOUND_FILE_SYMBOL_INTERPRETATIONS.has_key? key
                  message = "Unrecogized sound file identifier #{key.inspect}. " +
                        "Supported: " + SOUND_FILE_SYMBOL_INTERPRETATIONS.keys.map(&:inspect).to_sentence
                  raise ArgumentError, message
                end
                @sound_files[SOUND_FILE_SYMBOL_INTERPRETATIONS[key]] = value
              end
            end