code: def create_wallet(self, master_secret=b""):
          
          master_secret = deserialize.bytes_str(master_secret)
          bip32node = control.create_wallet(self.testnet,
                                            master_secret=master_secret)
          return bip32node.hwif(as_private=True)
docs: Create a BIP0032-style hierarchical wallet.
  
          @param: master_secret Create from master secret, otherwise random.