code: def signature_unsafe(m, sk, pk, hash_func=H):
      
      h = hash_func(sk)
      a = 2 ** (b - 2) + sum(2 ** i * bit(h, i) for i in range(3, b - 2))
      r = Hint(bytearray([h[j] for j in range(b // 8, b // 4)]) + m)
      R = scalarmult_B(r)
      S = (r + Hint(encodepoint(R) + pk + m) * a) % l
      return bytes(encodepoint(R) + encodeint(S))
docs: Not safe to use with secret keys or secret data.
      See module docstring.  This function should be used for testing only.