in lib/aws-record/record/transactions.rb [285:301]
def _transform_update_record(update_record, opts)
opts[:table_name] = update_record.class.table_name
opts[:key] = update_record.send(:key_values)
dirty_changes = update_record.send(:_dirty_changes_for_update)
update_expression_opts = update_record.class.send(
:_build_update_expression,
dirty_changes
)
opts = update_record.class.send(
:_merge_update_expression_opts,
update_expression_opts,
opts
)
{ update: opts }
end