How can I implement custom user model validation in my application?

How can I implement custom user model validation in my application?

You can implement custom user model validation by defining validation rules in your model class. What framework are you using?

I'm using Django. Can you give me an example?

Sure! In Django, you can override the clean method in your model to add custom validation logic. Would you like to see a code snippet?

Yes, please! That would be really helpful.

Here's a simple example:

from django.core.exceptions import ValidationError

class User(models.Model):
    username = models.CharField(max_length=150)

    def clean(self):
        if not self.username.isalnum():
            raise ValidationError('Username must be alphanumeric.')