def DeregisterAttributeContainer(cls, attribute_container_class):
    """Deregisters an attribute container class.

    The attribute container classes are identified based on their lower case
    container type.

    Args:
      attribute_container_class (type): attribute container class.

    Raises:
      KeyError: if attribute container class is not set for
                the corresponding container type.
    """
    container_type = attribute_container_class.CONTAINER_TYPE.lower()
    if container_type not in cls._attribute_container_classes:
      raise KeyError(
          'Attribute container class not set for container type: '
          '{0:s}.'.format(attribute_container_class.CONTAINER_TYPE))

    del cls._attribute_container_classes[container_type]