method.rb

  def self.purchase_as_guest_with_data(data)
    s = create_student_from_data(data)
    p = create_parent_from_data(data)

    s_user = User.new
    s_user.contact     = s
    s_user.email       = s.email
    s_user.password    = data[:student][:password]

    p_user = User.new
    p_user.contact     = p
    p_user.email       = p.email
    p_user.password    = data[:student][:password]

    tickets = data[:ticket_allocation_ids].map do |id|
      t = Ticket.new
      t.ticket_allocation_id = id
      t.contact = s
      t.purchase_date = Date.today
      t
    end

    begin
      ActiveRecord::Base.transaction do
        s.save!
        p.save!
        s_user.save!
        p_user.save!
        tickets.each { |t| t.save! }
      end
    rescue ActiveRecord:InvalidRecord # Or something
    end
    
    # There's no need for an explict return in Ruby
    [s, p, s_user, p_user] + tickets