code: def _list_merge(src, dest):
      
      for k in src:
          if type(src[k]) != dict:
              dest[k] = src[k]
          else:
              # ---
              # src could have a key whose value is a list
              # and does not yet exist on dest
              if k not in dest:
                  dest[k] = {}
              _list_merge(src[k], dest[k])
docs: Merge the contents coming from src into dest
  
      :param src: source dictionary
      :param dest: destination dictionary