anchor.diff:  does_fulfills_guid_constraints(
       UserCtx, SessionDiscriminator, FileCtx, AllGuidConstraints
   ) ->
  -    FileGuid = file_ctx:get_guid_const(FileCtx),
  +    FileGuid = get_file_guid(FileCtx),
       CacheKey = {guid_constraint, SessionDiscriminator, FileGuid},
   
       case permissions_cache:check_permission(CacheKey) of
  
positive.code:         SessionAuth ->
              SessionAuth
      end.
  
negative.code:     {true, file_ctx:ctx()} |
      {false, token_utils:guid_constraints(), file_ctx:ctx()}.
  check_and_cache_guid_constraints_fulfillment(FileCtx, CacheKey, GuidConstraints) ->
      FileGuid = get_file_guid(FileCtx),
      RemainingGuidConstraints = lists:filter(fun(GuidsSet) ->
          not lists:member(FileGuid, GuidsSet)
      end, GuidConstraints),
  