How to perform input validation for read-only instance attributes?

Question

A very similar question was posted here, but there are no accepted answers, no code examples and I don't really like the idea of using an external library as suggested by the only one answer provided there.

The following code allows to define read-only instance attributes:

class Point:
    def __init__(self, x, y):
        self._x = x
        self._y = y

    @property
    def x(self):
        return self._x

    @property
    def y(self):
        return self._y

but I would like to validate the user inputs as well. I want to validate if x and y have the right type.

What is the most pythonic/elegant way for doing this? If I provide setters, the attributes are no more read-only.

Is performing the input validation within the constructor the only way to go?