anchor.diff:  %% ====================================================================
   %% @doc Renders provider's name.
   %% @end
  --spec providerName(ProviderName :: binary()) -> Result when
  +-spec providerName(ProviderName :: binary() | undefined) -> Result when
       Result :: #p{}.
   %% ====================================================================
   providerName(undefined) ->
  
positive.code: %% ====================================================================
  %% @doc Renders urls.
  %% @end
  -spec urls(URLs :: [binary()]) -> Result when
      Result :: #p{}.
  %% ====================================================================
  urls(undefined) ->
  
negative.code: %% ====================================================================
  %% @doc Renders redirection point.
  %% @end
  -spec redirection_point(RedirectionPoint :: binary() | undefined) -> Result when
      Result :: #p{}.
  %% ====================================================================
  redirection_point(undefined) ->
  