text: from os.path import dirname
  
  TTL_IN_SECOND = 'EX'
  TTL_IN_MILLISECOND = 'PX'
  
  STATUS_OK = 0
  STATUS_WRONG_COMMAND = 1
  STATUS_SERVER_ERROR = 2
  STATUS_EXISTENCE_NOT_SATISFIED = 3
  
  _lua_path = dirname(__file__) + '/lua'
  
  
  def load_lua_script(key_type, command, replacements=None):
      with open('%s/%s/%s.lua' % (_lua_path, key_type, command)) as f:
          lua = f.read()
      if replacements is not None:
          for k in replacements:
              lua = lua.replace(k, replacements[k])
      return lua
      
      
  def wrap_with_single_quote(fields):
      return ['\'' + f + '\'' for f in fields]
  
  
  def expand_dict_to_list(dic):
      args = []
      for k in dic:
          args += [k, str(dic[k])]
      return args
  
  
  def wrap_dict_to_list(dic):
      return wrap_with_single_quote(expand_dict_to_list(dic))
  
  
  def to_string(value):
      return value if isinstance(value, str) else str(value)
  
  
  def to_strings(values):
      return [x if isinstance(x, str) else str(x) for x in values]
  
  
  def to_string_dict(dic):
      string_dic = {}
      for k in dic:
          string_dic[k] = dic[k] if isinstance(dic[k], str) else str(dic[k])
      return string_dic
  