Write an $\_\_$init$\_\_$ method that requires three parameters in addition to the self parameter:

The first parameter has no default value.

The second parameter has 'Unknown' as the default value.

The third parameter has 'Unknown' as the default value.

In the $\_\_$init$\_\_$ method, assign instance attributes:

travel$\_$time with the first parameter.

airport$\_$code with the second parameter.

seat with the third parameter.