Replacing data in lists

Question

def substituir(lista,velho,novo):
    lista = [1,2,3,3,5]
    resultado = substituir(lista[velho],novo)
    return resultado 

The problem is that I can’t replace an old list item with a new one.

For example if I put substituir(lista, 2, 99)

Indices with value 2 would be replaced with the value 99

Example:

Before:

lista = [1,2,3,2,4]

Afterward:

[1,99,3,99,4]