Update to support Markdown 3.4

.github/workflows/tests.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}

mdx_attr_cols.py

@@ -1,7 +1,8 @@
 """ Bootstrap 3 grid extension fo Python Markdown
 """
 
-from markdown.util import etree
+from xml.etree import ElementTree as etree
+
 from markdown import Extension
 from markdown.treeprocessors import Treeprocessor
 

tests.py

@@ -1,9 +1,9 @@
 from unittest import TestCase
+from xml.etree import ElementTree as etree
 
 import xmltodict
 
 from markdown import Markdown
-from markdown.util import etree
 
 from mdx_attr_cols import AttrColTreeProcessor, AttrColExtension, makeExtension
 
@@ -90,7 +90,7 @@ def test_extend_markdown(self):
     def test_missing_attr_list(self):
         md = self.mk_markdown(['mdx_outline'])
         ext = AttrColExtension({})
-        self.assertRaisesRegexp(
+        self.assertRaisesRegex(
             RuntimeError,
             "The attr_cols markdown extension depends the following"
             " extensions which must preceded it in the extension list:"
@@ -101,7 +101,7 @@ def test_missing_attr_list(self):
     def test_missing_outline(self):
         md = self.mk_markdown([])
         ext = AttrColExtension({})
-        self.assertRaisesRegexp(
+        self.assertRaisesRegex(
             RuntimeError,
             "The attr_cols markdown extension depends the following"
             " extensions which must preceded it in the extension list:"