old_contents: # Generated by Django 3.2 on 2021-05-03 10:32
  
  from django.db import migrations, models
  import django.db.models.deletion
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('exercises', '0012_auto_20210327_1219'),
      ]
  
      operations = [
          migrations.RenameField(
              model_name='exerciseimage',
              old_name='exercise',
              new_name='exercise_base',
          ),
          migrations.AlterField(
              model_name='exercisebase',
              name='license_author',
              field=models.CharField(blank=True, help_text='If you are not the author, enter the name or source here. This is needed for some licenses e.g. the CC-BY-SA.', max_length=50, null=True, verbose_name='Author'),
          ),
          migrations.AlterField(
              model_name='exercisebase',
              name='variations',
              field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='exercises.variation', verbose_name='Variations'),
          ),
      ]
  
new_contents: # Generated by Django 3.2 on 2021-05-03 10:32
  
  from django.db import migrations, models
  import django.db.models.deletion
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('exercises', '0012_auto_20210327_1219'),
      ]
  
      operations = [
          migrations.RenameField(
              model_name='exerciseimage',
              old_name='exercise',
              new_name='exercise_base',
          ),
          migrations.AlterField(
              model_name='exercisebase',
              name='license_author',
              field=models.CharField(blank=True,
                                     help_text='If you are not the author, enter the name or source '
                                               'here. This is needed for some licenses e.g. the '
                                               'CC-BY-SA.',
                                     max_length=50,
                                     null=True,
                                     verbose_name='Author'),
          ),
          migrations.AlterField(
              model_name='exercisebase',
              name='variations',
              field=models.ForeignKey(blank=True,
                                      null=True,
                                      on_delete=django.db.models.deletion.CASCADE,
                                      to='exercises.variation',
                                      verbose_name='Variations'),
          ),
      ]
  
subject: Fix pep8 errors