GoF design pattern with Python - Visitor

visitor.py

"""http://peter-hoffmann.com/2010/extrinsic-visitor-pattern-python-inheritance.html"""

class Node(object):
	pass

class A(Node):
	pass

class B(Node):
	pass

class C(A, B):
	pass

class Visitor(object):
	def visit(self, node, *args, **kwargs):
		meth = None
		for cls in node.__class__.__mro__:
			meth_name = 'visit_' + cls.__name__
			meth = getattr(self, meth_name, None)
			if meth:
				break

		if not meth:
			meth = self.generic_visit
		return meth(node, *args, **kwargs)

	def generic_visit(self, node, *args, **kwargs):
		print('generic_visit ' + node.__class__.__name__)

	def visit_B(self, node, *args, **kwargs):
		print('visit_B ' + node.__class__.__name__)

a = A()
b = B()
c = C()
visitor = Visitor()
visitor.visit(a)
visitor.visit(b)
visitor.visit(c)

Why not just: visitor = getattr(self, method, self.generic_visit) as in default ast library?