def reset_persisted_children
      _children.each do |child|
        child.move_changes
        child.new_record = false
      end
      _reset_memoized_children!
    end
def reset_persisted_children
      _children.each do |child|
        child.move_changes
        child.new_record = false
      end
      _reset_memoized_children!
    end
After children are persisted we can call this to move all their changes
 and flag them as persisted in one call.

 @example Reset the children.
   document.reset_persisted_children

 @return [ Array<Document> ] The children.

 @since 2.1.0