I noticed that is_valid_seed_len only accepts exact lengths of 128, 256, or 512 bits

However, BIP32 specifies a range rather than discrete values.

Generate a seed byte sequence S of a chosen length (between 128 and 512 bits; 256 bits is advised) from a (P)RNG.

Meaning we are rejecting valid seed lengths in between (e.g. 192 or 384 bits).

I wonder if this limitation has some specific reason or was caused by an oversight.

Found using the bitcoinfuzz tool.