old_contents: from django.db import models
  
  # Create your models here.
  
new_contents: from django.db import models
  from django.utils.encoding import python_2_unicode_compatible
  from django.contrib.auth.models import User
  #Problems: id,title, statement, output, uploadedby
  #2. Admins: id, name, email, passwordhash
  #3. Students: id, name, email, passwordhash
  @python_2_unicode_compatible
  class Problem(models.Model):
      problem_id = models.AutoField(primary_key=True)
      title = models.CharField(max_length=50,unique=False)
      statement = models.CharField(max_length=1000,unique=False)
      output = models.CharField(max_length=100,unique=False)
      uploadedby = models.ForeignKey('Admin',verbose_name="problem-setter")
      class Meta:
          verbose_name='problem'
          ordering = ['id']
  
subject: Add model for 'Problems'.