code: def true_negatives(links_true, links_pred, total):
      
  
      links_true = _get_multiindex(links_true)
      links_pred = _get_multiindex(links_pred)
  
      if isinstance(total, pandas.MultiIndex):
          total = len(total)
  
      return int(total) - len(links_true | links_pred)
docs: Count the number of True Negatives.
  
      Returns the number of correctly predicted non-links, also called the
      number of True Negatives (TN).
  
      Parameters
      ----------
      links_true: pandas.MultiIndex, pandas.DataFrame, pandas.Series
          The true (or actual) links.
      links_pred: pandas.MultiIndex, pandas.DataFrame, pandas.Series
          The predicted links.
      total: int, pandas.MultiIndex
          The count of all record pairs (both links and non-links). When the
          argument is a pandas.MultiIndex, the length of the index is used.
  
      Returns
      -------
      int
          The number of correctly predicted non-links.