old_contents: from __future__ import unicode_literals
  
  from django.db import models
  from django.contrib.auth.models import User
  from enum import Enum
  
  class DataType(Enum):
      """
      Enumeration of valid file types
      """
      pass
      # Leaving this blank until enum values are determined. 
      #NC=1
      #DAT=2
      #JSON=3
  
  class BaseModel(models.Model):
      """
      A simple base model to subclass from when we want to keep track of create and modify dates
      """
      created_date = models.DateTimeField(auto_now_add=True)
      modified_date = models.DateTimeField(auto_now_add=True)
  
      class Meta:
          """
          Declare this class abstract
          """
          abstract = True
  
  # Create your models here.
  class Notification(models.Model):
      user = models.CharField(max_length=100)
      notification_list = models.TextField()
  
  class DataFile(BaseModel):
      """
      Model of data stored by the users
      Inherit date fields from BaseModel
      """
      path = models.CharField(max_length=255)
      display_name = models.CharField(max_length=255)
      owner = models.ForeignKey('User')
      allowed_access = models.ManyToManyField(User)
      data_type = models.IntegerField(DataType)
new_contents: from __future__ import unicode_literals
  
  from django.db import models
  from django.contrib.auth.models import User
  from enum import Enum
  
  class DataType(Enum):
      """
      Enumeration of valid file types
      """
      pass
      # Leaving this blank until enum values are determined. 
      #NC=1
      #DAT=2
      #JSON=3
  
  class BaseModel(models.Model):
      """
      A simple base model to subclass from when we want to keep track of create and modify dates
      """
      created_date = models.DateTimeField(auto_now_add=True)
      modified_date = models.DateTimeField(auto_now_add=True)
  
      class Meta:
          """
          Declare this class abstract
          """
          abstract = True
  
  # Create your models here.
  class Notification(models.Model):
      user = models.CharField(max_length=100)
      notification_list = models.TextField()
  
  class DataFile(BaseModel):
      """
      Model of data stored by the users
      Inherit date fields from BaseModel
      """
      path = models.CharField(max_length=255)
      display_name = models.CharField(max_length=255)
      owner = models.ForeignKey(User)
      allowed_access = models.ManyToManyField(User)
      data_type = models.IntegerField(DataType)
  
subject: Update models.py