Block tag are invalid

I wrote block tag, when I try to cause it in template I got an error:

Invalid block tag: 'endyoutube'

My tag

from django import template

register = template.Library()

@register.tag
def youtube(parser, token):
    link = parser.parse(('endyoutube', ))
    iframe = """<iframe width="640" height="510" src="%s" frameborder="0" 
        allowfullscreen></iframe>""" % link
    return YoutubeNode(iframe)

class YoutubeNode(template.Node):
    def __init__(self, iframe):
        self.iframe = iframe

    def render(self, context):
        video = self.iframe.render(context)
        return video

te开发者_如何转开发mplate

{% load customtags %}
{% youtube %}
    http://www.youtube.com/watch?v=yZt1qXnOOqU
{% endyoutube %}

What is wrong in my tag? How could I fix it?

---

I got it. First mistake - I didn't use delete_first_token(), it's deleting closing tag from tokens, it was the cause of the error. Second mistake - this is impossible insert a parsed data into a string in function, because it's not a string, but class 'django.template.debug.DebugNodeList'. This object requires render() method to be a string caused in Node class instance. And the last one - youtube link for embed and for watch are different.

Workable tag

class YoutubeNode(template.Node):
    def __init__(self, parsed_link):
        self.parsed_link = parsed_link

    def render(self, context):
        del_it = re.compile('&feature=related')
        replace_it = re.compile('watch\?v=')
        link = self.parsed_link.render(context)
        link = del_it.sub('', link)
        link = replace_it.sub('embed/', link)
        video = """<p><iframe width="550" height="438" src="%s" 
        frameborder="0" allowfullscreen></iframe></p>""" % link
        return video

@register.tag
def youtube(parser, token):    
    parsed_link = parser.parse(('endyoutube', ))
    # first token it's closing tag. delete_first_token just delete it - del    self.tokens[0];)
    parser.delete_first_token()
    return YoutubeNode(parsed_link)