code: def _expand_data(self, old_data, new_data, group):
          
          for file in old_data:
              if file:
                  extension = file.split(".")[-1].lower()
                  if extension in self.file_types.keys():
                      new_data['groups'][group].append(self._expand_one_file(normpath(file),
                                                                             new_data, extension))
                  else:
                      logger.debug("Filetype for file %s not recognized" % file)
          if hasattr(self, '_expand_sort_key'):
              new_data['groups'][group] = sorted(new_data['groups'][group],
                                                 key=self._expand_sort_key)
docs: data expansion - uvision needs filename and path separately.