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class SoftDeleteQuerySet(models.QuerySet):
  @transaction.atomic
  def delete(self, snapshot_id=None):
    [x.delete(snapshot_id=snapshot_id) for x in self]


class SoftDeleteQueryManager(models.Manager):
  def __init__(self, *args, **kwargs):
    self.with_deleted = kwargs.pop('with_deleted', False)
    super(SoftDeleteManager, self).__init__(*args, **kwargs)

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class User(SoftDeleteModel):
  name = models.CharField(null=False, blank=False)
  
class Cat(SoftDeleteModel):
  owner = models.ForeignKey(
    User,
    null=True,
    blank=True,
    on_delete=models.SET_NULL)

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class Snapshot(models.Model):
  # unique identifier for snapshots
  id = models.Charfield(max_length=32)
  # the record which initiated the snapshot
  root_id = models.CharField(max_length=32)

  @transaction.atomic
  def restore(self):
    [x.restore() for x in self.snapshot_records.all()]
    self.delete()

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class Car(models.Model):
  # CASCADE is the default behavior. When this car's manufacturer is deleted,
  # this car will also be deleted
  manufacturer = models.ForeignKey(Manufacturer,  on_delete=models.CASCADE)

  # SET_NULL makes it so when this car's owner gets deleted, it will continue
  # to exist without an owner.
  owner = models.ForeignKey(User, on_delete=models.SET_NULL)

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class SoftDeleteManager(models.Manager):
  def __init__(self, *args, **kwargs):
    self.with_deleted = kwargs.pop('deleted', False)
    super(SoftDeleteManager, self).__init__(*args, **kwargs)

  def _base_queryset(self):
    return super().get_queryset().filter(deleted_at=None)

  def get_queryset(self):
    qs = self._base_queryset()

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# horrible!
User.objects.filter(first_name='Ian', is_deleted=False).first()

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class SoftDeleteModel(BaseModel):
  class meta:
      abstract = True
      
  is_deleted = models.DateTimeField(null=False, default=False)

  def delete(self):
    self.is_deleted = True
    self.save()

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class BaseModel(models.Model):
  created_at    = models.DateTimeField(auto_now_add=True)
  modified_date = models.DateTimeField(auto_now=True)

  class Meta:
    abstract = True

    # other fields / methods...

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package main

import (
	"errors"
	"fmt"
	"reflect"
)

func pipe(fns []interface{}, args ...interface{}) (interface{}, error) {
	for i := range fns {

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#include <stdio.h>
#include <pthread.h>

#define THREAD_COUNT 30

// Each thread will run an
// instance of this function
void *worker(void *arg) {
  printf("I'm worker #%d\n", (int)arg);
  return NULL;