docs: def clear_tags(my_expnum, ops_set, my_ccds, dry_run=True):
      """
      Clear the tags for the given expnum/ccd set.
      @param ops:
      @param my_expnum:
      @return:
      """
  
      for ops in ops_set:
        for fake in ops[0]:
          for my_program in ops[1]:
              for version in ops[2]:
                  props = {}
                  for ccd in my_ccds:
                      # print my_expnum, fake, my_program, version, ccd
                      key = storage.get_process_tag(fake + my_program, ccd, version)
                      props[key] = None
                  if not dry_run:
                      storage.set_tags(my_expnum, props)
                  else:
                      sys.stdout.write(" ".join(props)+"\n")