# File lib/fog/aws/requests/compute/modify_snapshot_attribute.rb, line 20
        def modify_snapshot_attribute(snapshot_id, attributes)
          params = {}
          params.merge!(Fog::AWS.indexed_param('CreateVolumePermission.Add.%d.Group', attributes['Add.Group'] || []))
          params.merge!(Fog::AWS.indexed_param('CreateVolumePermission.Add.%d.UserId', attributes['Add.UserId'] || []))
          params.merge!(Fog::AWS.indexed_param('CreateVolumePermission.Remove.%d.Group', attributes['Remove.Group'] || []))
          params.merge!(Fog::AWS.indexed_param('CreateVolumePermission.Remove.%d.UserId', attributes['Remove.UserId'] || []))
          request({
            'Action'        => 'ModifySnapshotAttribute',
            'SnapshotId'    => snapshot_id,
            :idempotent     => true,
            :parser         => Fog::Parsers::Compute::AWS::Basic.new
          }.merge!(params))
        end