bulk_fetcher_example.py

from typing import List

from .models import Customer

def bulk_fetch_customer(ids:List[int]) -> List[Customer]:
    hash_table = {
        instance.pk: instance
        for instance in ModelClass.objects.filter(id__in=ids)
    }
    instances = []
    not_found = []
    for id in ids:
        try:
            instances.append(hash_table[id])
        except Customer.DoesNotExist:
            not_found.append(id)
    if not_found:
        raise Customer.DoesNotExist("Customers with the following id don't exist: " + str(not_found))
    return instances