text: import sys
  
  from django.db import models
  
  from django.contrib.auth.models import (
      Group, Permission, AbstractBaseUser, PermissionsMixin, BaseUserManager)
  
  
  class CustomUserManager(BaseUserManager):
      def _create_user(self, username, email, password,
                       is_staff, is_superuser, is_active=True, **extra_fields):
          """
          Creates and saves a User with the given username, email and password.
          """
          if not username:
              raise ValueError('The given username must be set')
          email = self.normalize_email(email)
          user = self.model(username=username, email=email,
                            is_staff=is_staff, is_active=is_active,
                            is_superuser=is_superuser, **extra_fields)
          user.set_password(password)
          user.save(using=self._db)
          return user
  
      def create_user(self, username, email=None, password=None, **extra_fields):
          return self._create_user(username, email, password, False, False,
                                   **extra_fields)
  
      def create_superuser(self, username, email, password, **extra_fields):
          return self._create_user(username, email, password, True, True,
                                   **extra_fields)
  
  
  class CustomUser(AbstractBaseUser, PermissionsMixin):
      username = models.CharField(max_length=100, unique=True)
      email = models.EmailField(max_length=255, blank=True)
      is_staff = models.BooleanField(default=True)
      is_active = models.BooleanField(default=True)
      first_name = models.CharField(max_length=50, blank=True)
      last_name = models.CharField(max_length=50, blank=True)
  
      USERNAME_FIELD = 'username'
      REQUIRED_FIELDS = ['email']
  
      objects = CustomUserManager()
  
      def get_full_name(self):
          return self.first_name + ' ' + self.last_name
  
      def get_short_name(self):
          return self.first_name
  
  
  class EmailUserManager(BaseUserManager):
      def _create_user(self, email, password,
                       is_staff, is_superuser, **extra_fields):
          """
          Creates and saves a User with the given email and password.
          """
          email = self.normalize_email(email)
          user = self.model(email=email, is_staff=is_staff, is_active=True,
                            is_superuser=is_superuser, **extra_fields)
          user.set_password(password)
          user.save(using=self._db)
          return user
  
      def create_user(self, email=None, password=None, **extra_fields):
          return self._create_user(email, password, False, False,
                                   **extra_fields)
  
      def create_superuser(self, email, password, **extra_fields):
          return self._create_user(email, password, True, True,
                                   **extra_fields)
  
  
  class EmailUser(AbstractBaseUser):
      # Cant inherit from PermissionsMixin because of clashes with
      # groups/user_permissions related_names.
      email = models.EmailField(max_length=255, unique=True)
      is_staff = models.BooleanField(default=True)
      is_active = models.BooleanField(default=True)
      first_name = models.CharField(max_length=50, blank=True)
      last_name = models.CharField(max_length=50, blank=True)
  
      is_superuser = models.BooleanField(default=False)
      groups = models.ManyToManyField(Group, related_name='+', blank=True)
      user_permissions = models.ManyToManyField(Permission, related_name='+', blank=True)
  
      USERNAME_FIELD = 'email'
  
      objects = EmailUserManager()
  
      def get_full_name(self):
          return self.first_name + ' ' + self.last_name
  
      def get_short_name(self):
          return self.first_name
  
  
  def steal_method(name):
      func = getattr(PermissionsMixin, name)
      if sys.version_info < (3,):
          func = func.__func__
      setattr(EmailUser, name, func)
  
  methods = ['get_group_permissions', 'get_all_permissions', 'has_perm',
             'has_perms', 'has_module_perms']
  for method in methods:
      steal_method(method)
  