sub test_filelist_format {
    my $obj = shift;
    my $args = Parser::args2hash (@_);
    
    my $input = $args->{'input'};
    my $format =  $args->{'format'};

    if (!$input || !$format) {
	die("input file or format missing!\n");
    }
    
    ## if not list readable, return -1
    if ( $obj->is_readable(file=>$input) < 0 ) {return -1}

    ...

    my $formatstatus = test_format ("input" => $line, "format" => $format); 

    ...

}

sub test_format {

    my $obj = shift;
    my $args = Parser::args2hash (@_);

    my $input = $args->{'input'};
    my $format =  $args->{'format'};
    my $gzip = $args->{'gzip'};
    my $columns = $args->{'columns'};

    if (!$input || !$format) {
	die("input file or format missing!\n");
    }

    if ( $obj->is_readable(file=>$input) < 0 ) {return -1};

    ...
}