code: def _get_default_name_size(self, instance_type, size):
          
          if 'root_size' in self.images[instance_type]:
              size = self.images[instance_type].pop('root_size')
  
          if 'root_device' in self.images[instance_type]:
              name = self.images[instance_type].pop('root_device')
          else:
              name = '/dev/sda1'
  
          return name, size
docs: Checks if root device name/size were specified in the image definition.
  
          :param instance_type: A section name in amazon.json.
          :type instance_type: str
          :param size:
          :type size: int
          :return: Root device name and size
          :rtype: tuple(str, int)