Please take a look at the todo part and help with the following code! Thank you so much!

package fp;

import java.math.BigDecimal;

import java.util.ArrayList;

import java.util.Comparator;

import java.util.Map;

import java.util.function.

$*$

;

import java.util.stream.Collectors;

import java.util.List;

class ExerciseNotCompletedException extends RuntimeException

$\{$

$$ public ExerciseNotCompletedException

$($

$)$

$\{$

$$ super

$($

$"$

Exercise is not completed yet"

$)$

;

$$

$\}$

$\}$

$/$

$*$

$*$

$$

$*$

$\{$

@link HW

$\}$

$$is an exercise class. Each method returns a functional interface and it should be implemented

$$

$*$

$$using either lambda or a method reference. Every method that is not implemented yet throws

$$

$*$

$\{$

@link ExerciseNotCompletedException

$\}$

$.$

$$

$*$

$$

$$

$*$

$$TODO: remove exception and implement each method of this class using lambda or method reference

$$

$*$

$/**$

$*$ Returns a $\{$@link BiFunction$\}$ which first parameter is a $\{$@link Map$\}$ where key is a function name, and value is some

$*\{$@link IntUnaryOperator$\},$ and second parameter is a $\{$@link String$\}$ which is a function name. If the map contains a

$*$ function by a given name then it is returned by high order function otherwise an identity$()$ is returned.

$*$

$*$ @return a high$-$order function that fetches a function from a function map by a given name or returns identity$()$

$*/$

public static BiFunction, String, IntUnaryOperator$>$ functionLoader$()\{$

throw new ExerciseNotCompletedException$()$;

$\}$

$/**$

$*$ Returns a comparator of type T that is comparing values extracted using the provided mapper function.

$*$

$*$ E$.$g$.$ imagine you need to compare accounts by their balance values.

$*$

$*$ PLEASE NOTE, that @$\{$@link Comparator$\}$ is a functional interface, and you should manually write a lambda expression

$*$ to implement it$.$

$*$

$*$ @param mapper a mapper function that allows to map an object to a comparable value

$*$ @return a comparator instance

$*/$

public static $>$ Comparator comparing$($Function mapper$)\{$

throw new ExerciseNotCompletedException$()$;

$\}$

$/**$

$*$ Returns a comparator of type T that uses a provided comparator to compare objects, and only if they are equal

$*$ it's comparing values extracted using the provided mapper function.

$*$

$*$ E$.$g$.$ suppose you want to compare accounts by balance, but in case two people have the same balance you want to

$*$ compare their first names:

$*$

$*$

$*$ @param comparator an initial comparator

$*$ @param mapper a mapper function that is used to extract values when initial comparator returns zero

$*$ @return a comparator instance

$*/$

public static $>$ Comparator thenComparing$($

Comparator comparator, Function mapper$)\{$

throw new ExerciseNotCompletedException$()$;

$\}$

$/**$

$*$ Returns $\{$@link Supplier$\}$ of $\{$@link Supplier$\}$ of $\{$@link Supplier$\}$ of $\{$@link String$\}$ "WELL DONE!".

$*$

$*$ @return a supplier instance

$*/$

public static Supplier$>>$ trickyWellDoneSupplier$()\{$

throw new ExerciseNotCompletedException$()$;

$\}$

public static void main$($String$[]$ args$)\{$

ArrayList l $=$ new ArrayList$<>()$;

l$.$add$("$a$")$;

l$.$add$("$bc$")$;

l$.$add$("$dcf$")$;

System.out.println$($map$($l$,($String x$)->\{$ return x$.$length$()$;$\}))$;

$//$ U $=$ String, V $=$ Integer $[1,2,3]$

$\}$

$\}$