Django Project Blueprint: having exceptions on chapter 1

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Hi,
I'm just at the end of the BlueBlog (chapter 1) of this book and it raises an exception.
I don't know if I miss something but there's a strange oversight variable in urls.py (see: pdf file):
p.50: the url called is 'share-blog-post' but it's not defined anywhere in urls before (or even after)?
I tried to re-define in urls.py the SharePostWithBlog method, but it's not working.
Any idea?
BTW: don't forget to define all the CBVs in urls.py from blog.views (or it's not even recognized by the IDE)