docs: def unregister(self, items):
          """
          Remove items from registry.
  
          :param items:
          """
          items = _listify(items)
          # get all members of Registry except private, special or class
          meta_names = (m for m in vars(self).iterkeys()
                        if (not m.startswith('_') and m not in dir(Registry)))
          # check that meta names matches
          # FIXME: this is so lame. replace this with something more robust
          for m in meta_names:
              if m not in self.meta_names:
                  raise AttributeError('Meta name %s not listed.')
          # pop items from Registry and from meta
          for it in items:
              if it in self:
                  self.pop(it)
              for m in (getattr(self, m_) for m_ in self.meta_names):
                  if it in m:
                      m.pop(it)