Giving implementation to customize_DQM

Backup solution if PR 1834 is still evolving, in which case PR 1869 also needs to change. @yiiyama will not be available to take care of that. Since what PR 1869 is supposed to do is just add 20 lines to 1834, orthogonal to other developments, the solution here is to merge the change already in 1834 and close 1869.