def set(self, fmt, offset, value):
        """
        Set the value of a given bitfield.

        :param fmt: format-string for the bitfield being read, e.g. u8 for an
            unsigned 8-bit integer.
        :param int offset: offset (in number of bits).
        :param int value: value to set at the given position.
        :returns: a :py:class:`BitFieldOperation` instance.
        """
        bfo = BitFieldOperation(self.database, self.key)
        return bfo.set(fmt, offset, value)