prevent <hn> to call convert_hn and crash

fixes #142

Author: AlexVonB

Diff for: markdownify/__init__.py

@@ -213,7 +213,7 @@ def __getattr__(self, attr):
             n = int(m.group(1))
 
             def convert_tag(el, text, convert_as_inline):
-                return self.convert_hn(n, el, text, convert_as_inline)
+                return self._convert_hn(n, el, text, convert_as_inline)
 
             convert_tag.__name__ = 'convert_h%s' % n
             setattr(self, convert_tag.__name__, convert_tag)
@@ -311,7 +311,8 @@ def convert_code(self, el, text, convert_as_inline):
 
     convert_kbd = convert_code
 
-    def convert_hn(self, n, el, text, convert_as_inline):
+    def _convert_hn(self, n, el, text, convert_as_inline):
+        """ Method name prefixed with _ to prevent <hn> to call this """
         if convert_as_inline:
             return text
 

Diff for: tests/test_conversions.py

@@ -134,6 +134,7 @@ def test_hn():
     assert md('<h5>Hello</h5>') == '\n##### Hello\n\n'
     assert md('<h6>Hello</h6>') == '\n###### Hello\n\n'
     assert md('<h10>Hello</h10>') == md('<h6>Hello</h6>')
+    assert md('<hn>Hello</hn>') == md('Hello')
 
 
 def test_hn_chained():