a$.$ have a Pet interface that exports abstract methods for the String name$()$ and int age$()$ of the pet.

b$.$ create a Lizard and Dog class that both implement the Pet interface.

c$.$ make Pet sortable$/$comparable to other Pet objects, i$.$e$.$: interface Pet extends Comparable $\{..\}$

$($NB: Comparable is a standard java interface one can use to "tag" you custom object$/$type as being 'naturally sortable' via the java collections framework$)$

d$.$ implement the required compareTo$(..)$ method $--$ we'll say for any two pets p$1,$ p$2,$ that p$1$ 'comes before' p$2$ if p$1.$age$()<$ p$2.$age$()$

e$.$ add a PetRepo class that encapsulates a list of Pet objects currently in the pet shop. This class should have the following public API:

$-$void sort$()$ method that sorts the underlying collection of pets using Collections.sort$(...)$

$-$void add$($Pet p$)$ takes a pet and adds it to the list of Pet objects

$-$void clear$()$ empties out the pets list

$-$String toString$()$ override toString to render to the toString for each pet on its own line.

Next, add a package for the view and the event handling logic. Follow the approach demonstrated and worked so far in class.