code: def ratio(self, ratio):
          
          if isinstance(ratio, tuple):
              self._ratio = ratio
          else:
              raise TypeError('Invalid ratio type: %s' % type(ratio))
docs: The split ratio of the corporate action - i.e. the ratio of new shares to old shares
          :param ratio: A tuple representing (original_count, new_count).  For example (1, 2) is a doubling stock split.
          (3, 1) is a 3:1 reverse stock split.
          :return: