Objects and validation

[python at lists.fastmail.net]

I have a routine in Python which is extracting information from a
website. This information is read and inserted into objects.

I currently have all the validations and checks implemented in the
routines which are reading the HTML and creating the objects. It is
however also possible to move all the validations into the class itself.
What is considered the best practice for this: validation in the
functions which read the information and creates the objects or in the
class itself?

Thijs