anchor.diff:  
   %% @doc Similar to `get_value(Key, List, 0)' but converting the result into 
   %% an `integer()' or `error'.
  --spec get_integer(term(), list()) -> 
  +-spec get_integer(term(), list()) ->
       integer() | error. 
   
   get_integer(Key, List) ->
  
positive.code: 
  
  %% @doc Converts a gmt `datetime()' to a `timestamp()'.
  -spec local_to_timestamp(calendar:datetime()) -> 
      timestamp().
  
  local_to_timestamp(DateTime) ->
  
negative.code: 
  
  %% @doc Requivalent to `proplists:get_value/3' but faster.
  -spec get_value(term(), list(), term()) ->
      term().
  
  get_value(Key, List, Default) ->
  