Ruby self.private_method vs private_method

gistfile1.rb

class MyClass
  def foo
    puts baz
  end

  def bar
    puts self.baz
  end

  private

  def baz
    "baz"
  end
end

my_class = MyClass.new

my_class.foo

my_class.bar

# ---- Output ----
# baz
# test.rb:10:in `bar': private method `baz' called for #<MyClass:0x007fb413082810> (NoMethodError)
#   from test.rb:24:in `<main>'