Example of case not working with class

gistfile1.txt

xeno@xeno-Latitude-E7450:~/garage/ex15$ ruby try3.rb 
trace Array
NOPE
trace String
NOPE
trace MyThingy
NOPE
trace Hash
NOPE
xeno@xeno-Latitude-E7450:~/garage/ex15$ cat try3.rb 
class MyThingy
end

def caseyMeth(someArg)
    puts "trace #{someArg.class}"
    case someArg.class
    when Array
        puts "Array"
    when String
        puts "String"
    when MyThingy
        puts "MyThingy"
    else
        puts "NOPE"
    end
end

caseyMeth(Array.new)
caseyMeth("Some string")
caseyMeth(MyThingy.new)
caseyMeth(Hash.new)
xeno@xeno-Latitude-E7450:~/garage/ex15$