code: def fade_speed(self, value):
          
  
          if value is not None:
              assert type(value) is float, "'{0}' attribute: '{1}' type is not 'float'!".format("fade_speed", value)
              assert value >= 0, "'{0}' attribute: '{1}' need to be exactly positive!".format("fade_speed", value)
          self.__fade_speed = value
docs: Setter for **self.__fade_speed** attribute.
  
          :param value: Attribute value.
          :type value: float