godot-demos/2018/04-24-finite-state-machine/ 'previous' not working

[MikyGus]

I'm submitting a...

• [x ] Bug report.
• Feature request.

Bug report

What is the current behavior?
The 'previous' functionality is not working

What is the expected behavior?
To go to the previous state

Tell us the steps to reproduce the bug, and if possible share a minimal demo of the problem.

Found the problem in '/player_v2/state_machine.gd'
func _change_state(state_name):
if not _active:
return
current_state.exit()

if state_name == "previous":
	states_stack.pop_front()
else:
	states_stack[0] = states_map[state_name] <-- **Remove this**
        states_stack.push_front(states_map[state_name]) <-- **Replace with this**

current_state = states_stack[0]
emit_signal("state_changed", current_state)

if state_name != "previous":  <-- **Remove this**
	current_state.enter() <-- **We whant to enter the previous state**