docs: def getItems(self, specfiles=None, sort=False, reverse=False,
                   selector=None):
          """Generator that yields filtered and/or sorted :class:`Si` instances
          from ``self.sic``.
  
          :param specfiles: filenames of ms-run files - if specified return only
              items from those files
          :type specfiles: str or [str, str, ...]
          :param sort: if "sort" is specified the returned list of items is sorted
              according to the :class:`Si` attribute specified by "sort", if the
              attribute is not present the item is skipped.
          :param reverse: bool, ``True`` reverses the sort order
          :param selector: a function which is called with each ``Si`` item
              and returns True (include item) or False (discard item). Default
              function is: ``lambda si: True``
  
          :returns: items from container that passed the selector function
          """
          selector = (lambda si: True) if selector is None else selector
          if specfiles is None:
              specfiles = [_ for _ in viewkeys(self.info)]
          else:
              specfiles = aux.toList(specfiles)
          return _getItems(self.sic, specfiles, sort, reverse, selector)