2127       default: Optional default value; if omitted, an empty list is used.

  2127       default: Optional default value; if omitted, an empty list is used.

  2128       **kwds: Optional additional keyword arguments, passed to base class.

  2128       **kwds: Optional additional keyword arguments, passed to base class.

  2129 

  2129 

  2130     Note that the only permissible value for 'required' is True.

  2130     Note that the only permissible value for 'required' is True.

  2131     """

  2131     """

  2132     if not isinstance(item_type, type):

  2134     if not isinstance(item_type, type):

  2133       raise TypeError('Item type should be a type object')

  2135       raise TypeError('Item type should be a type object')

  2134     if item_type not in _ALLOWED_PROPERTY_TYPES:

  2136     if item_type not in _ALLOWED_PROPERTY_TYPES:

  2135       raise ValueError('Item type %s is not acceptable' % item_type.__name__)

  2137       raise ValueError('Item type %s is not acceptable' % item_type.__name__)

  2136     if 'required' in kwds and kwds['required'] is not True:

  2138     if 'required' in kwds and kwds['required'] is not True: