def unset(i)
      check_range(i)
      w = self.word_index(i)
      return if w.nil?

      result = @words[w] &= ~(1 << i % BITS_PER_WORD)
      result
    end
def unset(i)
      check_range(i)
      w = self.word_index(i)
      return if w.nil?

      result = @words[w] &= ~(1 << i % BITS_PER_WORD)
      result
    end
Unsets (unflags) given bit. This method allows bits to be unset more than once in a row, no exception will be raised.

 @param [Integer] A bit to unset
 @api public