True / False
The classical [7,4,3] Hamming code has parity-check matrix H with rows 0001111, 0110011, 1010101. A CSS code can be built from a single classical code when that code is dual-containing, i.e. H H^T = 0 (mod 2). Computing H H^T mod 2 for this H, is every entry zero (so the construction is valid)?