Union initializes any Table-derived type to point to the union at
           the given offset.

def Union(self, t2, off):
        """Union initializes any Table-derived type to point to the union at
           the given offset."""
        assert type(t2) is Table
        N.enforce_number(off, N.UOffsetTFlags)

        off += self.Pos
        t2.Pos = off + self.Get(N.UOffsetTFlags, off)
        t2.Bytes = self.Bytes