docs: def forwards(self, orm):
          "Write your forwards methods here."
          db.execute('DELETE FROM cohort_variant')
          db.execute('DELETE FROM cohort_sample')
          db.execute('DELETE FROM cohort')
  
          samples = orm['samples.Sample'].objects.filter(published=True)
          count = samples.count()
          cohort = orm['samples.Cohort'](name='World', autocreated=True,
              published=bool(count), count=count)
          cohort.save()
  
          cohort_samples = []
          for sample in samples:
              cohort_samples.append(orm['samples.CohortSample'](object_set=cohort, set_object=sample))
  
          orm['samples.CohortSample'].objects.bulk_create(cohort_samples)
  
          for project in orm['samples.Project'].objects.all():
              samples = orm['samples.Sample'].objects.filter(published=True, project=project)
              count = samples.count()
              cohort = orm['samples.Cohort'](project=project, name=project.label,
                  autocreated=True, published=bool(count), count=count)
              cohort.save()
  
              cohort_samples = []
              for sample in samples:
                  cohort_samples.append(orm['samples.CohortSample'](object_set=cohort, set_object=sample))
  
              orm['samples.CohortSample'].objects.bulk_create(cohort_samples)
  
          for batch in orm['samples.Batch'].objects.select_related():
              samples = orm['samples.Sample'].objects.filter(published=True, batch=batch)
              count = samples.count()
              cohort = orm['samples.Cohort'](batch=batch, project=batch.project,
                  name='{0}: {1}'.format(batch.project.label, batch.label), autocreated=True,
                  published=bool(count), count=count)
              cohort.save()
  
              cohort_samples = []
              for sample in samples:
                  cohort_samples.append(orm['samples.CohortSample'](object_set=cohort, set_object=sample))
  
              orm['samples.CohortSample'].objects.bulk_create(cohort_samples)