old_contents: from __future__ import unicode_literals
  
  from django.db import models, migrations
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('portal', '0009_add_precomputed_rna_table'),
      ]
  
      operations = [
          # rna_type is a / seperated field that represents the set of rna_types
          # for a given sequence.
          migrations.AddField("RnaPrecomputed", "rna_type", models.CharField(max_length=250))
      ]
  
new_contents: from __future__ import unicode_literals
  
  from django.db import models, migrations
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('portal', '0007_add_precomputed_rna_table'),
      ]
  
      operations = [
          # rna_type is a / seperated field that represents the set of rna_types
          # for a given sequence.
          migrations.AddField("RnaPrecomputed", "rna_type", models.CharField(max_length=250))
      ]
  
subject: Correct prerequisites