Excellent: Using python: Design a class named Fan to represent a fan. The class contains: Three constants named SLOW, MEDIUM, and FAST with the values 1, 2, and 3 to denote the fan speed. A private int data field named speed that specifies the speed of the fan (the default is SLOW). A private boolean data field named on that specifies whether the fan is on the default is false). A private double data field named radius that specifies the radius of the fan (the default is 5). A string data field named colour that specifies the colour of the fan (the default is blue). The accessor and mutator methods for all four data fields. A method named_str_method to return the string description of the class If the fan is on, the method returns the fan speed, colour, and radius in one combined string. If the fan is not on, the method returns the fan colour and radius along with the string "fan is off" in one combined string. Write a test program that creates two Fan objects. Assign maximum speed, radius 12, colour green, and turn it on to the first object. Assign medium speed, radius 6, colour red, and turn it off to the second object. Display the objects by invoking their __str_method