code: def one(self):
          
          row = None
          if self._current_rows:
              try:
                  row = self._current_rows[0]
              except TypeError:  # generator object is not subscriptable, PYTHON-1026
                  row = next(iter(self._current_rows))
  
          return row
docs: Return a single row of the results or None if empty. This is basically
          a shortcut to `result_set.current_rows[0]` and should only be used when
          you know a query returns a single row. Consider using an iterator if the
          ResultSet contains more than one row.