Increasing depth in python

[malling]

I think i came up with something. I basicly just repeated the steps from previous task. the apply(left, right, state)

def step(rules, state):
  result=[]
  for x in state:
     if x==rules:
        result.append(state)
     else:
        result.append(x)

[inner for outer in result for inner in outer]

print(result)

#This funktion is not made yet. Dont think about it!!!
def compute(depth, rules, start):
  print()

step("F",["F","L","F","R","F","L","F"])   

Now i just need to flatten it but it didn't seem to work as planned.

Update!!!

I found out how to remove the brackets but still haven't removed 2 outer ones. any ideer?
I did this:

def step(rules, state):
   result=[]
   for x in state:
       if x==rules:
           result.append(state)
       else:
           result.append(x)
   
   flatten = [inner for outer in result for inner in outer]
   print(flatten)

#This funktion is not made yet. Dont think about it!!!
def compute(depth, rules, start):
   print()
   
step("F",["F","L","F","R","F","L","F"])

and got this

Output:
['F', 'L', 'F', 'R', 'F', 'L', 'F', 'L', 'F', 'L', 'F', 'R', 'F', 'L', 'F', 'R', 'F', 'L', 'F', 'R', 'F', 'L', 'F', 'L', 'F', 'L', 'F', 'R', 'F', 'L', 'F']

But as you see i still need to remove the last 2 at each side.