Fix in visitor doctests

Cython/Compiler/Visitor.py

@@ -25,16 +25,16 @@ class BasicVisitor(object):
             # Must resolve, try entire hierarchy
             pattern = "visit_%s"
             mro = inspect.getmro(cls)
+            handler_method = None
             for mro_cls in mro:
-                try:
+                if hasattr(self, pattern % mro_cls.__name__):
                     handler_method = getattr(self, pattern % mro_cls.__name__)
                     break
-                except AttributeError:
-                    pass
-            else:
+            if handler_method is None:
                 print type(self), type(obj)
                 if hasattr(self, 'access_path'):
                     print self.access_path
+                    if self.access_path:
                         print self.access_path[-1][0].pos
                         print self.access_path[-1][0].__dict__
                 raise RuntimeError("Visitor does not accept object: %s" % obj)
@@ -60,7 +60,7 @@ class TreeVisitor(BasicVisitor):
     
     Example:
     
-    >>> class SampleNode:
+    >>> class SampleNode(object):
     ...     child_attrs = ["head", "body"]
     ...     def __init__(self, value, head=None, body=None):
     ...         self.value = value