code: def add(self, files, items):
          
          if isinstance(files, (str, bytes)):
              files = iter([files])
          for pathname in files:
              try:
                  values = self._filemap[pathname]
              except KeyError:
                  self._filemap[pathname] = items
              else:
                  values.extend(items)
docs: Add a list of files with a reference to a list of objects.