I am trying to execute a simple command on a host. I get output but with a warning.

Use of uninitialized value in concatenation (.) or string at /usr/local/share/perl5/Net/SSH/Perl/Key.pm line 13, <$fh> line 7.

Use of uninitialized value in concatenation (.) or string at /usr/local/share/perl5/Net/SSH/Perl/Key.pm line 13, <$fh> line 8.

Use of uninitialized value in concatenation (.) or string at /usr/local/share/perl5/Net/SSH/Perl/Key.pm line 13, <$fh> line 9.

Use of uninitialized value in concatenation (.) or string at /usr/local/share/perl5/Net/SSH/Perl/Key.pm line 13, <$fh> line 10

here is my code:

use Net::SSH::Perl;
$username="root";
$passwd="password";
@server = ("10.14.34.80");

my %SSH_Prm = (
            "protocol"         => '2',
            "options"          => ["stricthostkeychecking no"],
        );

foreach $a(@server)
{
  $ssh = Net::SSH::Perl->new($a,%SSH_Prm);
  $ssh->login($username, $passwd);
  $cmd="hostname";
  my($stdout, $stderr,$exit) = $ssh->cmd("$cmd");
  print "$stdout";
}
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