class A
  def extend_me(x)
    x + 1
  end
end

# We need to change the way our method works, but retain the original behavior
# too.
class A
  old_method = public_instance_method(:extend_me)
  define_method(:extend_me) do |x|
    puts "Inside the new version"
    x *= 3
    old_method.bind(self).call(x)
  end
end