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 offset: offset (in number of bits). If prefixed with a
            '#', this is an offset multiplier, e.g. given the arguments
            fmt='u8', offset='#2', the offset will be 16.
        :param int value: value to set at the given position.
        :returns: a :py:class:`BitFieldOperation` instance.
        """
        self.operations.append(('SET', fmt, offset, value))
        return self