from jinja2 import nodes
from jinja2.ext import Extension

class TestExtension(Extension):
    tags = {'test_ext'}
    def parse(self, parser): return nodes.Const("This is test extension")

[((6, 36, 6, 73), 'jinja2.nodes.Const', 'nodes.Const', ({(6, 48, 6, 72): '"""This is test extension"""'}, {}), "('This is test extension')", False, 'from jinja2 import nodes\n')]