anchor.diff:          OptionDefinitions = default(Role),
           InitialMap =
               maps:fold(
  -              fun({K,def}, #{default:=V}, M) -> M#{K=>V};
  +              fun(K, #{default:=V}, M) -> M#{K=>V};
                    (_,_,M) -> M
                 end,
                 Opts0#{user_options => 
  
positive.code: 
  %%%================================================================
  %%%
  %%% Default options
  %%%
  
  
negative.code: 
  
  check_fun(Key, Defs) ->
      #{chk := Fun} = maps:get(Key, Defs),
      Fun.
  
  %%%================================================================
  