display-accts: drop python 2 compat logic

BUG=None
TEST=`./display-accts.py --lint` works

Change-Id: I83a0f1e578482336230b7414c13adb51d46f751b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/eclass-overlay/+/3779420
Commit-Queue: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
diff --git a/profiles/base/accounts/display-accts.py b/profiles/base/accounts/display-accts.py
index 26da0f4..7c275de 100755
--- a/profiles/base/accounts/display-accts.py
+++ b/profiles/base/accounts/display-accts.py
@@ -1,13 +1,10 @@
 #!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 # Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Pretty print (and check) a set of group/user accounts"""
 
-from __future__ import print_function
-
 import argparse
 import collections
 import glob
@@ -16,6 +13,10 @@
 import sys
 
 
+assert sys.version_info >= (3, 6), (
+    f'Python 3.6+ required, but found {sys.version_info}')
+
+
 # Regex to match valid account names.
 VALID_ACCT_NAME_RE = re.compile(r'^[a-z][a-z0-9_-]*[a-z0-9]$')