Default attribute values

default_vals.py

from pynamodb.models import Model
from pynamodb.attributes import UnicodeAttribute


def make_id():
    return somerandomid

class Thread(Model):
    table_name = 'Thread'
    forum_name = UnicodeAttribute(hash_key=True)
    another_field = UnicodeAttribute(hash_key=True)

def __init__(self, *args, **kwargs):
    custom_id = make_id()
    kwargs.setdefault("forum_name", custom_id)
    kwargs.setdefault("another_field", custom_id)
    super(Thread, self).__init__(*args, **kwargs)