Update cmp to py3 functions, update map return to list for py3

qa/rpc-tests/key_import_export.py

@@ -1,11 +1,10 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Copyright (c) 2017 The Zcash developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or https://www.opensource.org/licenses/mit-license.php .
 
-import sys; assert sys.version_info < (3,), ur"This script does not run under Python 3. Please use Python 2.7.x."
-
 from decimal import Decimal
+from functools import reduce
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_greater_than, start_nodes, initialize_chain_clean, connect_nodes_bi
 
@@ -40,11 +39,8 @@ class KeyImportExportTest (BitcoinTestFramework):
 
         def verify_utxos(node, amounts):
             utxos = node.listunspent(1, 10**9, [addr])
-
-            def cmp_confirmations_high_to_low(a, b):
-                return cmp(b["confirmations"], a["confirmations"])
-
-            utxos.sort(cmp_confirmations_high_to_low)
+            utxos.sort(key=lambda x: x["confirmations"])
+            utxos.reverse()
 
             try:
                 assert_equal(amounts, [utxo["amount"] for utxo in utxos])
@@ -66,7 +62,7 @@ class KeyImportExportTest (BitcoinTestFramework):
         verify_utxos(charlie, [])
 
         # the amounts of each txn embodied which generates a single UTXO:
-        amounts = map(Decimal, ['2.3', '3.7', '0.1', '0.5', '1.0', '0.19'])
+        amounts = list(map(Decimal, ['2.3', '3.7', '0.1', '0.5', '1.0', '0.19']))
 
         # Internal test consistency assertion:
         assert_greater_than(