text: from django.db import models
  
  
  class CompanyManager(models.Manager):
      def getCompanies(self, order_by='name'):
          return super(CompanyManager, self).get_queryset().extra(order_by=[order_by])
  
  class CategoryManager(models.Manager):
      def getCategories(self, order_by='name'):
          return super(CategoryManager, self).get_queryset().extra(order_by=[order_by])
  