code: def bip32_seed(self, s):
          
          pair = parse_colon_prefix(s)
          if pair is None or pair[0] not in "HP":
              return None
          if pair[0] == "H":
              try:
                  master_secret = h2b(pair[1])
              except ValueError:
                  return None
          else:
              master_secret = pair[1].encode("utf8")
          return self._network.keys.bip32_seed(master_secret)
docs: Parse a bip32 private key from a seed.
          Return a :class:`BIP32 <pycoin.key.BIP32Node.BIP32Node>` or None.