Django parallel test runner setup_databases function

gistfile1.py

...
def setup_databases(self, **kwargs):
  if VERSION[0] == 1:
    if VERSION[1] == 2 and VERSION[2] < 4:
      return self.setup_databases_12(**kwargs)
    elif VERSION[2] >= 4 or VERSION[1] == 3:
      return self.setup_databases_13(**kwargs)

  raise Exception('Unsupported Django Version: %s' % (str(VERSION)))

def setup_databases_12(self, **kwargs):
  # Taken from django.test.simple
  old_names = []
  mirrors = []

  worker_index = kwargs.get('worker_index', None)
  for alias in connections:
    connection = connections[alias]
    database_name = 'test_%d_%s' % (worker_index, connection.settings_dict['NAME'])
    connection.settings_dict['TEST_NAME'] = database_name
    if connection.settings_dict['TEST_MIRROR']:
      mirrors.append((alias, connection))
      mirror_alias = connection.settings_dict['TEST_MIRROR']
      connections._connections[alias] = connections[mirror_alias]
    else:
      old_names.append((connection, connection.settings_dict['NAME']))
      connection.creation.create_test_db(verbosity=0, autoclobber=not self.interactive)
  return old_names, mirrors

def setup_databases_13(self, **kwargs):
  # Taken from django.test.simple
  from django.test.simple import dependency_ordered

  mirrored_aliases = {}
  test_databases = {}
  dependencies = {}

  worker_index = kwargs.get('worker_index', None)
  for alias in connections:
    connection = connections[alias]
    database_name = 'test_%d_%s' % (worker_index, connection.settings_dict['NAME'])
    connection.settings_dict['TEST_NAME'] = database_name

    item = test_databases.setdefault(
        connection.creation.test_db_signature(),
        (connection.settings_dict['NAME'], [])
    )
    item[1].append(alias)
    if alias != DEFAULT_DB_ALIAS:
      dependencies[alias] = connection.settings_dict.get('TEST_DEPENDENCIES', [DEFAULT_DB_ALIAS])

  old_names = []
  mirrors = []
  for signature, (db_name, aliases) in dependency_ordered(test_databases.items(), dependencies):
      connection = connections[aliases[0]]
      old_names.append((connection, db_name, True))
      test_db_name = connection.creation.create_test_db(verbosity=0, autoclobber=not self.interactive)
      for alias in aliases[1:]:
          connection = connections[alias]
          if db_name:
            old_names.append((connection, db_name, False))
            connection.settings_dict['NAME'] = test_db_name
          else:
            old_names.append((connection, db_name, True))
            connection.creation.create_test_db(verbosity=0, autoclobber=not self.interactive)

  for alias, mirror_alias in mirrored_aliases.items():
    mirrors.append((alias, connections[alias].settings_dict['NAME']))
    connections[alias].settings_dict['NAME'] = connections[mirror_alias].settings_dict['NAME']

  return old_names, mirrors
...