Consider file noname1.pm containing:

use strict;
use warnings;

package noname1;

sub new {
    return bless {};
}

1;
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and noname1.pl containing:

use strict;
use warnings;
use noname1;

package noname1;

sub doit {
    print "Hello world\n";
}

package main;

my $obj = noname1->new ();

$obj->doit ();
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Executing noname1.pl prints:

Hello world
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