TypeError: must be str, not int, don't understand what i'm doing wrong : I need help with the following code, because i can't understand what i'm doing wrong.
It's a function for my the game Minesweeper which receives a position like "C3" and has to return an int to search a position in a list of available positions.

    def evalua_jugada(posicion,posiciones_posibles):
    
    	"""Convierte a la posicion ingresada en un numero de la lista de posiciones posibles"""
    	
    indice_en_posiciones_posibles = (8 * list(ascii_uppercase).index(posicion[0].upper())) + (posicion[1] + 1) 
    	
    return(posiciones_posibles[indice_en_posiciones_posibles])

this is my very first post so i don't know how to ident well jajaja.
Anyway hope you can help me.``