How to Iterate un even Multi Dimensional Array global Programmatically

Hi Community,

I have created global with below values , now I want to iterate programatically.

^Book("Auto1","Properties","Color")="Red"
^Book("Auto1","Properties","Color1")="Yellow"
^Book("Auto1","Properties","Model")="SUV"
^Book("Auto2","Owner")="Prashanth"
^Book("Auto2","Properties","Color")="Green"
^Book("Color")="Red"
^Book("Color1")="Red"

i have used below method but only printing last2 elements properly

ClassMethod Iterate()
{
set subscript = ""
for {
set subscript = $order(^Book(subscript))
quit:(subscript = "")
write !, "subscript=", subscript, ", value=", ^Book(subscript)
}
}

Thanks,

Prashanth