fix syntax

I've removed the print condition, because it will just result in an error no matter what (sigh)

bin/lesson_check.py

@@ -392,14 +392,11 @@ def check_codeblock_classes(self):
 
         for node in self.find_all(self.doc, {'type': 'codeblock'}):
             cls = self.get_val(node, 'attr', 'class')
-            self.reporter.check(cls is not none and (cls in KNOWN_CODEBLOCKS or
+            self.reporter.check(cls is not None and (cls in KNOWN_CODEBLOCKS or
                 cls.startswith('language-')),
                                 (self.filename, self.get_loc(node)),
                                 'Unknown or missing code block type {0}',
                                 cls)
-            if not cls is None:
-                print("NOTE: The AST was malformed and needs to be investigated")
-                print(self.filename, self.get_loc(node))
 
     def check_defined_link_references(self):
         """Check that defined links resolve in the file.