I'm working through a book on Ruby, and the author used a slightly different form for writing a class initialization definition than he has in previous sections of the book. It looks like this:

class Ticket
  attr_accessor :venue, :date
  def initialize(venue, date)
    self.venue = venue
    self.date = date
  end
end

In previous sections of the book, it would've been defined like this:

class Ticket
  attr_accessor :venue, :date
  def initialize(venue, date)
    @venue = venue
    @date = date
  end
end

Is there any functional difference between using the setter method, as in the first example, vs. using the instance variable as in the second? They both seem to work. Even mixing them up works:

class Ticket
  attr_accessor :venue, :date
  def initialize(venue, date)
    @venue = venue
    self.date = date
  end
end