How to return double in CanFly speed(CanFly fly)?

Question about the task

Under discussion

public class Solution { public static void main(String[] args) { } interface CanMove{ Double spd = 1.1; default Double speed() { return spd; } } interface CanFly extends CanMove { default CanFly speed(CanFly fly){ return fly; } } }

1. Create a CanMove interface that has a speed method.
2. The speed method must return a Double and should not accept any arguments.
3. Make the CanFly interface inherit the CanMove interface.
4. Add the speed method to the CanFly interface.
5. The speed method must return a Double and accept one CanFly argument.

Requirements:

The Solution class must declare a CanMove interface.
The Solution class must declare a CanFly interface.
The CanFly interface must inherit the CanMove interface.
The CanMove interface must declare a speed method with no parameters and must return a Double.
The CanFly interface must declare a speed method with one CanFly parameter and must return a Double.

package com.codegym.task.task13.task1309; /* All that moves */ public class Solution { public static void main(String[] args) { } interface CanMove{ Double spd = 1.1; default Double speed() { return spd; } } interface CanFly extends CanMove { default CanFly speed(CanFly fly){ return 1.1; } } }