docs: def setdiff(list1, list2):
      """
      returns list1 elements that are not in list2. preserves order of list1
  
      Args:
          list1 (list):
          list2 (list):
  
      Returns:
          list: new_list
  
      Example:
          >>> # ENABLE_DOCTEST
          >>> from utool.util_list import *  # NOQA
          >>> import utool as ut
          >>> list1 = ['featweight_rowid', 'feature_rowid', 'config_rowid', 'featweight_forground_weight']
          >>> list2 = [u'featweight_rowid']
          >>> new_list = setdiff_ordered(list1, list2)
          >>> result = ut.repr4(new_list, nl=False)
          >>> print(result)
          ['feature_rowid', 'config_rowid', 'featweight_forground_weight']
      """
      set2 = set(list2)
      return [item for item in list1 if item not in set2]