def peek(self, fmt):
        """Interpret next bits according to format string and return result.

        fmt -- Token string describing how to interpret the next bits.

        The position in the bitstring is not changed. If not enough bits are
        available then all bits to the end of the bitstring will be used.

        Raises ReadError if not enough bits are available.
        Raises ValueError if the format is not understood.

        See the docstring for 'read' for token examples.

        """
        pos_before = self._pos
        value = self.read(fmt)
        self._pos = pos_before
        return value
Interpret next bits according to format string and return result.

        fmt -- Token string describing how to interpret the next bits.

        The position in the bitstring is not changed. If not enough bits are
        available then all bits to the end of the bitstring will be used.

        Raises ReadError if not enough bits are available.
        Raises ValueError if the format is not understood.

        See the docstring for 'read' for token examples.