sub fit_data {
    our @ydata;
    local *ydata = shift;
    print "array contains: ",join(",",@ydata)," \n";
    print "last index is $#ydata \n";
};;


sub fit_data {
    my @ydata = @{shift()};
    print "array contains: ",join(",",@ydata)," \n";
    print "last index is $#ydata \n";

}