- A new type object, 'string', is added. This is a common base type

- A new type object, 'string', is added.  This is a common base type
  for 'str' and 'unicode', and can be used instead of
  types.StringTypes, e.g. to test whether something is "a string":
  isinstance(x, string) is True for Unicode and 8-bit strings.  This
  is an abstract base class and cannot be instantiated directly.