Custom getter and setter for Django model fields

from django.db import models

class Person(models.Model):
    _first_name = models.CharField(max_length=30, db_column='first_name')
    last_name = models.CharField(max_length=30)

    @property
    def first_name(self):
        """your logic here, return value"""
        return "foo"

    @first_name.setter
    def first_name(self, value):
        self._first_name = value