How to make a function with Python data validation? type Try

Question

1. When I do this code outside a function it works, now when I do with function it returns me 0.

    ```
    def validacao(x):
        try:
            x = int(input())
            band = 1
        except ValueError:
            band = 0
        while band==0:
            print("Somente números!")
            try:
                x = int(input())
                band = 1
            except ValueError:
                band = 0
   
    print("1 - Inserir registro de um cliente")
    print("2 - Listar os registros dos Bebes")
    print("3 - Buscar pelo registro de um Bebe")
    op = 0
    validacao(op)
    ```