code: def _check_underflow(self, n):
          '''
          Raise BufferUnderflow if there's not enough bytes to satisfy
          the request.
          '''
          if self._pos + n > self._end_pos:
              raise self.BufferUnderflow(f _check_underflow(self, n):
          '''
          Raise BufferUnderflow if there's not enough bytes to satisfy
          the request.
          '''
          if self._pos + n > self._end_pos:
              raise self.BufferUnderflow()
docs: Raise BufferUnderflow if there's not enough bytes to satisfy
          the request.