code: def set_alpha_value(self, value):
          '''
          setter
          Learning rate.
          '''
          if isinstance(value, float) is False:
              raise TypeError("The type of __alpha_value must be float.")
          self.__alpha_value = valuf set_alpha_value(self, value):
          '''
          setter
          Learning rate.
          '''
          if isinstance(value, float) is False:
              raise TypeError("The type of __alpha_value must be float.")
          self.__alpha_value = value
docs: setter
          Learning rate.