code: def combine_nt_lists(lists, flds, dflt_null=""):
      
      combined_nt_list = []
      # Check that all lists are the same length
      lens = [len(lst) for lst in lists]
      assert len(set(lens)) == 1, \
          "LIST LENGTHS MUST BE EQUAL: {Ls}".format(Ls=" ".join(str(l) for l in lens))
      # 1. Instantiate namedtuple object
      ntobj = cx.namedtuple("Nt", " ".join(flds))
      # 2. Loop through zipped list
      for lst0_lstn in zip(*lists):
          # 2a. Combine various namedtuples into a single namedtuple
          combined_nt_list.append(ntobj._make(_combine_nt_vals(lst0_lstn, flds, dflt_null)))
      return combined_nt_list
docs: Return a new list of namedtuples by zipping "lists" of namedtuples or objects.