diff --git a/.gitignore b/.gitignore
index 92cd29a..dc3ef71 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,7 @@ __pycache__/
 .Python
 env/
 venv/
+.venv/
 venv2/
 venv3/
 build/
@@ -24,6 +25,7 @@ var/
 *.egg-info/
 .installed.cfg
 *.egg
+.eggs/
 
 # PyInstaller
 #  Usually these files are written by a python script from a template
diff --git a/markdown_blockdiag/extension.py b/markdown_blockdiag/extension.py
index 32826dc..aa65494 100644
--- a/markdown_blockdiag/extension.py
+++ b/markdown_blockdiag/extension.py
@@ -12,8 +12,8 @@ def __init__(self, **kwargs):
         }
         super(BlockdiagExtension, self).__init__(**kwargs)
 
-    def extendMarkdown(self, md, md_globals):
-        md.parser.blockprocessors.add(
+    def extendMarkdown(self, md):
+        md.parser.blockprocessors.register(
             'blockdiag', BlockdiagProcessor(md.parser, self), '>indent'
         )
         md.registerExtension(self)
diff --git a/markdown_blockdiag/parser.py b/markdown_blockdiag/parser.py
index 952aac2..86feb8d 100644
--- a/markdown_blockdiag/parser.py
+++ b/markdown_blockdiag/parser.py
@@ -3,7 +3,7 @@
 import base64
 
 from markdown.blockprocessors import BlockProcessor
-from markdown.util import etree
+import xml.etree.ElementTree as etree
 from markdown_blockdiag.utils import draw_blockdiag, DIAG_MODULES
 
 # Python 3 version