Custom validation feature request

[jae-lee]

Description

Would like to see a feature to implement custom validations that could span multiple fields. For example:

Let's say you had a vacation start date and vacation end date field. Vacation start date should be before vacation end date.

[kfollesdal]

@jae-lee maybe I misunderstand, but can you use post_init to validate dependent fields?

import typic
from datetime import datetime


@typic.klass
class DateCheck:
    start: datetime
    end: datetime

    def __post_init__(self):
        if self.start > self.end:
            raise ValueError("Start date have to be before end date.")

[MVrachev]

I agree this will be an awesome feature.
Many times you want a deeper validation beyond type checks which you can only implement.

What is the status of this issue?