anchor.diff:      m_find_value/3,
       m_to_list/2,
       m_value/2,
  -    url_for/1
  +    url_for/1,
  +    language_url_for/2
   ]).
   
   -include_lib("zotonic.hrl").
  
positive.code: m_find_value(url, #m{value = License}, _Context) ->
      url_for(License);
  m_find_value(language_url, #m{value = License}, Context) ->
      iolist_to_binary([
          url_for(License),
          <<"/deed.">>,
          z_convert:to_binary(z_context:language(Context))
      ]).
  
  m_to_list(_, _Context) ->
      [].
  
negative.code: m_value(_Source, _Context) ->
      undefined.
  
  %% @doc Get URL to license at the Creative Commons website
  -spec url_for(binary() | string()) -> binary() | undefined.
  url_for(License) when is_list(License) ->
      url_for(z_convert:to_binary(License));
  url_for(<<"BY">>) ->
  