Case statement don't work

I'm learning Ruby from "Programming Ruby, The Pragmatic Programmers(2nd, 2005)" and I'm stuck in the Case statement chapter. So i copy-paste some code in my version from book:

def kind
  puts "Type year and I'll tell you genre: "
  ask = gets.chomp

  kind = case ask
  when 1850..1889 then "Blues"
  when 1890..1909 then "Ragtime"
  when 1910..1929 then "New Orleans Jazz"
  when 1930..1939 then "Swing"
  when 1940..1950 then "Bebop"
  else "Jazz"
end


puts "You typed year #{ask}. Genre of music in that period is 
       #{kind}."
end

kind

Hence, whatever year I'm put, output is "Jazz"...What am I working incorrectly?