class Person
  def speak
    puts "Hey, Tj!"
  end

  def whisper_louder
    whisper
  end

  def whisper_self
    self.whisper
  end

  private 
  def whisper
    puts "His name's not really 'Tj'." 
  end 
end

p = Person.new

p.speak
p.whisper_louder

# should cause an error
# but in version 2.7.1 no error occurs
p.whisper_self