How to overwrite a function used in a module-method?

#!/usr/bin/env perl
use warnings;
use 5.012;
use utf8;

use WWW::Mechanize::Cached;
use Some::Module qw(some_method);

my $url = '...';
my $result = some_method( $url );

The some_method() uses itself get() form LWP::Simple.
How could I overwrite the get() with my my_get() in this script?

sub my_get {
    my $url;
    my $mech = WWW::Mechanize::Cached->new();
    $mech->get( $url );
    my $content = $mech->content( format => 'text' );
    return $content;
}