docs: def _printable_id_code(self):
          """
          Returns the code in a printable form, separating it into groups of
          three characters using a point between them.
  
          :return: the ID code in a printable form
          """
          code = super(ISWCCode, self)._printable_id_code()
  
          code1 = code[:3]
          code2 = code[3:6]
          code3 = code[-3:]
  
          return '%s.%s.%s' % (code1, code2, code3)