diff --git a/src/snek/system/markdown.py b/src/snek/system/markdown.py
index f0b6e25..ca603d8 100644
--- a/src/snek/system/markdown.py
+++ b/src/snek/system/markdown.py
@@ -24,17 +24,20 @@ class MarkdownRenderer(HTMLRenderer):
     def _escape(self, str):
         return str  ##escape(str)
 
+    def get_lexer(self, lang, default='bash'):
+        try:
+            return get_lexer_by_name(lang, stripall=True)
+        except:
+            return get_lexer_by_name(default, stripall=True)
+    
     def block_code(self, code, lang=None, info=None):
         if not lang:
             lang = info
         if not lang:
             lang = 'bash'
-            # return '\n<pre><code>%s</code></pre>\n' % escape(code)
-        lexer = get_lexer_by_name(lang, stripall=True)
+        lexer = self.get_lexer(lang)
         formatter = html.HtmlFormatter(lineseparator="<br>")
         result = highlight(code, lexer, formatter)
-        if not result:
-            return f"<pre>{escape(code)}</pre>"
         return result 
 
     def render(self):