anchor.diff:  -type db_parameter()    :: {ftype, failure_type()} |
                              {fprob, 0..100} |                                %failure probability
                              {fdest, failure_dest()} |                        %quadrants in which failures are inserted / if missing all is assumed
  -                           {distribution, db_generator:distribution()}.     %in every quadrant
  +                           {fdistribution, db_generator:distribution()} |   %distribution of failures
  +                           {distribution, db_generator:distribution()}.     %data distribution in every quadrant
   -type db_status() :: {Entries   :: non_neg_integer(),
                         Existing  :: non_neg_integer(),
                         Missing   :: non_neg_integer(),
  
positive.code: -export_type([distribution/0, db_type/0, db_parameter/0, db_status/0, failure_type/0]).
  -endif.
  
  -type distribution() :: uniform |
                          {non_uniform, random_bias:distribution_fun()}.
  -type result() :: ?RT:key() | 
                    {?RT:key(), ?DB:value()}.
  
negative.code:     {_LBr, LKey, RKey, _RBr} = intervals:get_bounds(I),
      I2 = intervals:new('(', LKey, RKey, ')'),
      Keys = get_db(I2, DBSize, Distr),
      {DB, DBStatus} = gen_kvv(proplists:get_value(fdistribution, Params, uniform), Keys, Params),
      insert_db(DB),
      DBStatus.
  
  fill_wiki(_DBSize, _Params) ->
      %TODO
      {0, 0, 0, 0}.
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  -spec insert_db(?DB:db_as_list()) -> ok.
  insert_db(KVV) ->
  