code: def inside_nonspeech(self, index):
          
          self._ensure_mfcc_mask()
          if (index < 0) or (index >= self.all_length) or (self.__mfcc_mask[index]):
              return None
          return self._binary_search_intervals(self.__nonspeech_intervals, index)
docs: If ``index`` is contained in a nonspeech interval,
          return a pair ``(interval_begin, interval_end)``
          such that ``interval_begin <= index < interval_end``,
          i.e., ``interval_end`` is assumed not to be included.
  
          Otherwise, return ``None``.
  
          :rtype: ``None`` or tuple