code: def _getItems(container, containerKeys=None, sort=False, reverse=False,
                selector=lambda item: True):
      
      if containerKeys is None:
          containerKeys = [_ for _ in viewkeys(container)]
      else:
          containerKeys = aux.toList(containerKeys)
  
      if sort:
          sortIdentifier = list()
          for containerKey in containerKeys:
              for identifier in [_ for _ in viewkeys(container[containerKey])]:
                  item = container[containerKey][identifier]
                  if selector(item):
                      try:
                          sortIdentifier.append((getattr(item, sort),
                                                 containerKey, identifier
                                                 )
                                                )
                      except AttributeError:
                          pass
          sortIdentifier.sort(key=ITEMGETTER(0), reverse=reverse)
          for _, containerKey, identifier in sortIdentifier:
              yield container[containerKey][identifier]
      else:
          for containerKey in containerKeys:
              for identifier in [_ for _ in viewkeys(container[containerKey])]:
                  item = container[containerKey][identifier]
                  if selector(item):
                      yield item
docs: Generator that yields filtered and/or sorted items from the specified
      "container".
  
      :param container: The container has to be a dictionary of dictionaries that
          contain some kind of items. Depending on the specified parameters all or
          a subset of these items are yielded.
          ``{containerKey1: {key1: item1, key2: item2, ...}, ...}``
      :param containerKeys: valid keys of the "container", if None all keys are
          considered.
      :type containerKeys: a single dictionary key or a list of keys
      :param sort: if "sort" is specified the returned list of items is sorted
          according to the item 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 item and returns
          True (include item) or False (discard item). If not specified all items
          are returned
  
      :returns: items from container that passed the selector function