test: use ExtendedPrivateKey in wallet_send.py

test/functional/wallet_send.py

@@ -8,6 +8,7 @@ from decimal import Decimal, getcontext
 from itertools import product
 
 from test_framework.descriptors import descsum_create
+from test_framework.extendedkey import ExtendedPrivateKey
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_not_equal,
@@ -204,8 +205,9 @@ class WalletSendTest(BitcoinTestFramework):
         # w2 contains the private keys for w3
         self.nodes[1].createwallet(wallet_name="w2", blank=True)
         w2 = self.nodes[1].get_wallet_rpc("w2")
-        xpriv = "tprv8ZgxMBicQKsPfHCsTwkiM1KT56RXbGGTqvc2hgqzycpwbHqqpcajQeMRZoBD35kW4RtyCemu6j34Ku5DEspmgjKdt2qe4SvRch5Kk8B8A2v"
-        xpub = "tpubD6NzVbkrYhZ4YkEfMbRJkQyZe7wTkbTNRECozCtJPtdLRn6cT1QKb8yHjwAPcAr26eHBFYs5iLiFFnCbwPRsncCKUKCfubHDMGKzMVcN1Jg"
+        extendedkey = ExtendedPrivateKey.generate()
+        xpriv = extendedkey.to_string()
+        xpub = extendedkey.pubkey().to_string()
         w2.importdescriptors([{
             "desc": descsum_create("wpkh(" + xpriv + "/0/0/*)"),
             "timestamp": "now",