title: TimeField and DurationField int error
body: <p>I have run into this error when running python manage.py migrate when using DurationField and TimeField both give me a:</p>
  
  <pre><code>return int(round(value.total_seconds() * 1000000))
  AttributeError: 'int' object has no attribute 'total_seconds'
  </code></pre>
  
  <p>I have seen this error on this site but only for a Django 1.8. Currently, I am using Django 1.10.
  I have tried these suggesions :</p>
  
  <pre><code>DurationField(default=timedelta()), 
  DurationField(), 
  DurationField(default=timedelta()), 
  DurationField(default=int(timedelta(minutes=20).total_seconds())). 
  </code></pre>
  
  <p>My model currently looks like:</p>
  
  <pre><code>class SomeModel(models.Model):
      user = models.OneToOneField(User, on_delete=models.CASCADE)
      lunchnumber = models.IntegerField(null=True, blank=True)
      role = models.PositiveSmallIntegerField(choices=ROLE_CHOICES,null=True, blank=True)
      breaktime = models.DurationField(default=timedelta(minutes=45))
  
      def to_python(self, value):
          if value is None:
              return value
          if isinstance(value, datetime.timedelta):
              return value
          try:
              parsed = parse_duration(value)
          except ValueError:
              pass
          else:
              if parsed is not None:
                  return parsed
  </code></pre>
  
  <p>Addressing Prakhar Trivedi's question:
  I do not know what value is not working well. I was under the assumption it was the default value that django is trying populate that database table with. I am under this impression because of 
      .......in get_db_prep_value
      return int(round(value.total_seconds() * 1000000))
      AttributeError: 'int' object has no attribute 'total_seconds'</p>
  
  <p>Addressing iklinac's Answer:</p>
  
  <p>I went in and added the default=timedelta(minutes=45). I do have it imported from datetime But I feel I am missing something. I am very new at this and have not seen a to_python function. What am I missing I am still getting the same error?</p>