old_contents: from django.db import models
  from django.core.exceptions import ValidationError
  
  import uuid # from http://zesty.ca/python/uuid.html
  import sys
  import base64 
  
  
  
   
  def fetch_code(custom_string="CODE_"):
      """
      usage:
      fetch_code()   
      fetch_code(custom_string="KEY_")
    
      """
      b64uid = '00000000'
      
     
      uid = uuid.uuid4()
      b64uid = base64.b64encode(uid.bytes,'-_')
      
      code = b64uid[0:6]
      return custom_string+code
  
  # Create your models here.
  class Msg( models.Model ):
      """
      Model for storing `messages`
      """
  
      def validate_file(fieldfile_obj):
          """
          Validation of size
          """
          filesize = fieldfile_obj.file.size
          kilobyte_limit = 65
          if filesize > kilobyte_limit*1024:
              raise ValidationError("Max file size is %skB" % str(kilobyte_limit))
  
      frame_id = models.CharField( max_length = 255, blank=True)
      timestamp = models.DateTimeField(auto_now_add=True)
      source = models.CharField( max_length = 255 )
      channel = models.CharField( max_length = 255 )
      signature = models.CharField( max_length = 255 )
      #body = models.FileField(upload_to="messages/%Y/%m/%d/", validators=[validate_file],blank=True)
  
      body = models.TextField(blank=True)
  
      def save(self, *args, **kwargs):
          self.frame_id = fetch_code(custom_string="0_")
          super(Msg, self).save(*args, **kwargs)
  
  
new_contents: from django.db import models
  from django.core.exceptions import ValidationError
  
  import uuid # from http://zesty.ca/python/uuid.html
  import sys
  import base64 
  
  
  def to_native(value):
      """ Return epoch time for a datetime object or ``None``"""
      import time
      try:
         return int(time.mktime(value.timetuple()))
      except (AttributeError, TypeError):
         return None
  
  
          
   
  def fetch_code(custom_string="CODE_"):
      """
      usage:
      fetch_code()   
      fetch_code(custom_string="KEY_")
    
      """
      b64uid = '00000000'
      
     
      uid = uuid.uuid4()
      b64uid = base64.b64encode(uid.bytes,'-_')
      
      code = b64uid[0:6]
      return custom_string+code
  
  # Create your models here.
  class Msg( models.Model ):
      """
      Model for storing `messages`
      """
  
      def validate_file(fieldfile_obj):
          """
          Validation of size
          """
          filesize = fieldfile_obj.file.size
          kilobyte_limit = 65
          if filesize > kilobyte_limit*1024:
              raise ValidationError("Max file size is %skB" % str(kilobyte_limit))
  
      frame_id = models.CharField( max_length = 255, blank=True)
      timestamp = models.DateTimeField(auto_now_add=True)
      source = models.CharField( max_length = 255 )
      channel = models.CharField( max_length = 255 )
      signature = models.CharField( max_length = 255 )
      #body = models.FileField(upload_to="messages/%Y/%m/%d/", validators=[validate_file],blank=True)
  
      body = models.TextField(blank=True)
      epoch = models.IntegerField()
  
      def save(self, *args, **kwargs):
          self.frame_id = fetch_code(custom_string="0_")
          self.epoch = to_native(self.timestamp)
          super(Msg, self).save(*args, **kwargs)
  
  
subject: Update models.py