I am trying to subclass in my code (see below). But I am getting the
following error while running the code.

song.rb:12: class/module name must be CONSTANT
class karaokeSong < Song
                   ^
song.rb:23: warning: don't put space before argument parentheses

Not able to figure why "<" is not being accepted for subclassing. I am
using 1.8.6 version on windows. Pls. help

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class Song
  def initialize (name, artist, duration)
    @name = name
    @artist = artist
    @duration = duration
   end
   def to_s
    "Song: #{@name}--#{@artist} #{@duration}"
    end
end

class karaokeSong < Song
  def initialize (name, artist, duration, lyrics)
    super(name, artist, duration)
    @lyrics = lyrics
  end
end

aSong = karaokeSong.new ("Bicyclops", "Fleck", 260, "And, now the")
puts aSong.inspect
puts aSong.to_s