next time just use

 --> ``` 
    some code
again this  --> ``` 

return "this" ? you could actually try to modify string and return string then, but better not to alter the passed data in :)

I also like this kata

next time you could use Meld application or some other diff tool to ease your value difference lookup. :)

this 96 is bad practice, isn't it?
if you want you could eval them before return statement imho and then use

...

question,what if we have:

A) state, level, event = ., 5, O
 so we closed the gate, advanced to end (closed fully) and got strange "obstacle"
from security perspective I think it should not start immediately action to open

B) state, level, event = None, 0, O
 so we get obstacle before we could even think about moving returning etc.
for me that means we should not move and treat it as '.' - wait (stay on 0 level)

C) what if we had state machine with "error"
input = "OOPOO" 
output= "00100"
if we had obstacle and never get "freed" from it, I think the "safe" should be ".P" only starts the gate close progression
 so assume "0" * 5:
output= "00000"
would be correct then

it's kinda tricky, but want to know if you thought about consequences of this exercise "in the wild"

FYI @chainsaw-maniac , @brendanvos