Insert node in specific index of linked list Python

Good, I have a doubt with this that I can not think of how to do it, as the title says, I have a typical node and a typical list

class node:
    def __init__(self, info):
        self.info = info
        self.next = None

class list:
    def __init__(self):
        self.__first = None
        self.__last = None

and I have to create the function that inserts the node in the specific position of the given list (I put here what I have) (I do not want to change something of the node, nor create methods)

def indexar(self, info, indice):
    longit = self.tam()
    n = node(info)
    p = self.__first
    if index == 0:
        self.__first = n
    else:
        if index > 0 and index < longit:

already create the function self.tam () that delivers the size of the list, and I already have in case you want to enter the position 0, but already for a non-initial X position I can not achieve it (rather, imagine it), any kind of help or recommendation is eternally grateful