class Net::IMAP

def search_internal(cmd, keys, charset)
  if keys.instance_of?(String)
    keys = [RawData.new(keys)]
  else
    normalize_searching_criteria(keys)
  end
  synchronize do
    if charset
      send_command(cmd, "CHARSET", charset, *keys)
    else
      send_command(cmd, *keys)
    end
    clear_responses("SEARCH").last || []
  end
end