anchor.diff:  -type get_options() :: [get_option()]. %% A list of options for a get request.
   -type put_options() :: [put_option()]. %% A list of options for a put request.
   -type search_options() :: [search_option()]. %% A list of options for a search request.
  --type delete_options() :: [delete_quorum()]. %% A list of options for a delete request.
  +-type delete_options() :: [delete_option()]. %% A list of options for a delete request.
   -type mapred_queryterm() ::  {map, mapred_funterm(), Arg::term(), Accumulate :: boolean()} |
                                {reduce, mapred_funterm(), Arg::term(),Accumulate :: boolean()} |
                                {link, Bucket :: riakc_obj:bucket(), Tag :: term(), Accumulate :: boolean()}.
  
positive.code:                       {if_modified, riakc_obj:vclock()} |
                        {notfound_ok, boolean()} |
                        {basic_quorum, boolean()} |
                        head | deletedvclock.
  
  
  %% Valid request options for get requests. When `if_modified' is
  
negative.code: %% returned. When `deletedvclock' is specified, the vector clock of
  %% the tombstone will be returned if the object has been recently
  %% deleted.
  -type put_option() :: write_quorum() | return_body | return_head | if_not_modified | if_none_match |
                        {n_val, pos_integer()} |
                        {sloppy_quorum, boolean()}.
  %% Valid request options for put requests. `return_body' returns the
  %% entire result of storing the object. `return_head' returns the
  %% metadata from the result of storing the object. `if_not_modified'
  