instance method fire

# File activemodel/lib/active_model/state_machine/event.rb, line 22
      def fire(obj, to_state = nil, *args)
        transitions = @transitions.select { |t| t.from == obj.current_state(@machine ? @machine.name : nil) }
        raise InvalidTransition if transitions.size == 0

        next_state = nil
        transitions.each do |transition|
          next if to_state && !Array(transition.to).include?(to_state)
          if transition.perform(obj)
            next_state = to_state || Array(transition.to).first
            transition.execute(obj, *args)
            break
          end
        end
        next_state
      end