For subroutines with more than one argument:

sub mysub {
    return unless( (@_ % 2) == 0);
    my %args = (
        host => 'localhost',
        port => 25,
        @_);
    #
    print "Args: host = $args{'host'}, port = $args{'port'}\n";
    1;
}

mysub( host => 'gatekeeper.dec.com', port => 80)
    or die "Mysub failed";
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