docs: def modify(self, entry_id, **kw):
      '''
      Incremental version of :meth:`update`: instead of updating all
      attributes of the entry to the specified values, this method only
      updates the specified keywords. Returns True on success, or raises
      an exception on failure.
  
      Note: the default implementation assumes fast and sequential access
      and reads the current version, updates the specified values, and
      calls :meth:`update`.
      '''
      entry = self.read(entry_id)
      for k, v in kw.items():
        setattr(entry, k, v)
      self.update(entry)
      return True