using variables in for loops using strings

So my issue is instead of writing

rooms == "south" or "South" or "s" or "S":

to get all the users inputs I would like to create a variable to replace all the extra souths that way I wont have to repeat the steps

Tried looking it up couldn't find anything also tried putting it in the function with multiple things. Thanks for the help guys first time using stack overflow

user = input("> ")

south = ("South" or "s" or "S" or "south")

   def bedroom():
       print(f"{user} looks around and there is 3 doors in the 
       room.")
       print("Do i take the South, East or West room?")
       rooms = input("> ")
           if rooms == south:
               print("You are now in the living room.")
               living_room()
           elif rooms == "East":
               print("You have entered the TREASURE ROOM!!!")
               treasure_room()