#!/usr/bin/perl
use strict;
use warnings;
use Data::Dump 'pp';
use Time::Piece;

use Date::Calc qw(:all);

.....

sub report{

....
my ($get_year, $get_week) = split /-/,$wk;
    my ($year2, $month2, $day2) = Monday_of_Week($get_week, $get_year);
    my $format_date = "$year2-$month2-$day2";
    my $get_time = Time::Piece->strptime($format_date, '%Y-%m-%d');
    print "\n".$get_time->fullmonth." ".$get_time->year." Week $get_week\n------------\n";

....

}