old_contents: 
  
  COUCH = 'couch'
  
new_contents: from corehq.util.couchdb_management import couch_config
  from pillowtop.dao.couch import CouchDocumentStore
  
  COUCH = 'couch'
  
  
  def get_document_store(data_source_type, data_source_name):
      if data_source_type == COUCH:
          return CouchDocumentStore(couch_config.get_db_for_db_name(data_source_name))
      else:
          raise NotImplementedError(
              'getting document stores for backend {} is not supported!'.format(data_source_type)
          )
  
subject: add get_document_store