docs: def multi_index_insert_row(df, index_row, values_row):
      """ Return a new dataframe with a row inserted for a multi-index dataframe.
          This will sort the rows according to the ordered multi-index levels.
      """
      row_index = pd.MultiIndex(levels=[[i] for i in index_row],
                                labels=[[0] for i in index_row])
      row = pd.DataFrame(values_row, index=row_index, columns=df.columns)
      df = pd.concat((df, row))
      if df.index.lexsort_depth == len(index_row) and df.index[-2] < df.index[-1]:
          # We've just appended a row to an already-sorted dataframe
          return df
      # The df wasn't sorted or the row has to be put in the middle somewhere
      return df.sort_index()