title: expected string or bytes-like object error
body: <p>when I run the migrate command I see that error. I don't know it comes from which my python files.
  I check my models with a new database but not diff.
  do you have any idea? Does it come from my models.py? my templates? my views? somewhere? </p>
  
  <pre><code>python.exe .\manage.py migrate
   Operations to perform:
   Apply all migrations: admin, auth, contenttypes, matab, sessions
  Running migrations:
  
    Applying matab.0032_auto_20190825_1010...Traceback (most recent call last):
    File ".\manage.py", line 21, in &lt;module&gt;
      main()
    File ".\manage.py", line 17, in main
      execute_from_command_line(sys.argv)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\__init__.py", line 381, in execute_from_command_line
      utility.execute()
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\__init__.py", line 375, in execute
      self.fetch_command(subcommand).run_from_argv(self.argv)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\base.py", line 323, in run_from_argv
      self.execute(*args, **cmd_options)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\base.py", line 364, in execute
      output = self.handle(*args, **options)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\base.py", line 83, in wrapped
      res = handle_func(*args, **kwargs)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\management\commands\migrate.py", line 234, in
  handle
      fake_initial=fake_initial,
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\migrations\executor.py", line 117, in migrate
      state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\migrations\executor.py", line 147, in _migrate_all_forwards
      state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\migrations\executor.py", line 245, in apply_migration
      state = migration.apply(state, schema_editor)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\migrations\migration.py", line 124, in apply
      operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\migrations\operations\fields.py", line 112, in database_forwards
      field,
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\backends\base\schema.py", line 433, in add_field
      definition, params = self.column_sql(model, field, include_default=True)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\backends\base\schema.py", line 161, in column_sql
      default_value = self.effective_default(field)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\backends\base\schema.py", line 233, in effective_default
      return field.get_db_prep_save(self._effective_default(field), self.connection)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\fields\__init__.py", line 789, in get_db_prep_save
      return self.get_db_prep_value(value, connection=connection, prepared=False)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\fields\__init__.py", line 1273, in get_db_prep_value
      value = self.get_prep_value(value)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\fields\__init__.py", line 1268, in get_prep_value
      return self.to_python(value)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\models\fields\__init__.py", line 1230, in to_python
      parsed = parse_date(value)
    File "C:\Users\Rahkar\AppData\Local\Programs\Python\Python36\lib\site-packages\django\utils\dateparse.py", line 74, in parse_date
      match = date_re.match(value)
  TypeError: expected string or bytes-like object
  </code></pre>
  
  <p>and here is my 0032_auto_20190825_1010 file:</p>
  
  <h1>Generated by Django 2.2.3 on 2019-08-25 05:40</h1>
  
  <pre><code>from django.db import migrations, models
  import django.db.models.deletion
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('matab', '0031_auto_20190819_1304'),
      ]
  
      operations = [
          migrations.RemoveField(
              model_name='turn',
              name='Patient',
          ),
          migrations.AddField(
              model_name='turn',
              name='Date',
              field=models.DateField(default=1),
              preserve_default=False,
          ),
          migrations.AddField(
              model_name='turn',
              name='Patient_FirstName',
              field=models.CharField(default=1, max_length=100),
              preserve_default=False,
          ),
          migrations.AddField(
              model_name='turn',
              name='Patient_LastName',
              field=models.CharField(default=1, max_length=100),
              preserve_default=False,
          ),
          migrations.AddField(
              model_name='turn',
              name='Section',
              field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='matab.Section'),
          ),
          migrations.AlterField(
              model_name='personalnfo',
              name='EducationLevel',
              field=models.CharField(blank=True, max_length=100, null=True),
          ),
          migrations.AlterField(
              model_name='turn',
              name='Doctor',
              field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='matab.Doctor'),
          ),
          migrations.AlterField(
              model_name='turn',
              name='Time',
              field=models.TimeField(),
          ),
      ]
  </code></pre>