Use old version if that's all we have

Author: multiplemonomials

tools/python/memap/memap.py

@@ -51,6 +51,7 @@
 from typing import Optional, TextIO
 from abc import abstractmethod, ABC
 from sys import stdout, exit, argv, path
+import sys
 from os import sep
 from os.path import (basename, dirname, join, relpath, abspath, commonprefix,
                      splitext)
@@ -61,6 +62,14 @@
 from copy import deepcopy
 from collections import defaultdict
 from prettytable import PrettyTable, HRuleStyle
+
+# prettytable moved this constant into an enum in the Python 3.9 release.
+if sys.version_info >= (3, 9):
+    from prettytable import HRuleStyle
+    HEADER = HRuleStyle.HEADER
+else:
+    from prettytable import HEADER
+
 from jinja2 import FileSystemLoader, StrictUndefined
 from jinja2.environment import Environment
 

tools/requirements.txt

@@ -1,4 +1,8 @@
-prettytable>=3.12.0 # 3.12.0 both added HRuleStyle and deprecated the old constants in one single release :/
+
+# 3.12.0 both added HRuleStyle and deprecated the old constants in one single release :/
+prettytable>=2.0,<3.12.0; python_version < '3.9'
+prettytable>=3.12.0; python_version >= '3.9'
+
 future>=0.18.0,<1.0
 jinja2>=2.11.3
 intelhex>=2.3.0,<3.0.0