def get_item_args(opts)
      opts[:base_shape] ||= 'Default'
      default_args = {
        item_shape: {base_shape: opts[:base_shape]},
        item_ids:   [{item_id:{id: id, change_key: change_key}}]
      }
      default_args[:item_shape][:body_type] = @body_type if @body_type
      default_args
    end
def get_item_args(opts)
      opts[:base_shape] ||= 'Default'
      default_args = {
        item_shape: {base_shape: opts[:base_shape]},
        item_ids:   [{item_id:{id: id, change_key: change_key}}]
      }
      default_args[:item_shape][:body_type] = @body_type if @body_type
      default_args
    end
Build up the arguements for #get_item
 @todo: should we really pass the ChangeKey or do we want the freshest obj?