code: def get_buildroot(self, worker_metadatas):
          
          buildroots = []
          for platform in sorted(worker_metadatas.keys()):
              for instance in worker_metadatas[platform]['buildroots']:
                  instance['id'] = '{}-{}'.format(platform, instance['id'])
                  buildroots.append(instance)
  
          return buildroots
docs: Build the buildroot entry of the metadata.
  
          :return: list, containing dicts of partial metadata