def load(self, filename, create_if_missing=True):
        filename = Path(filename)
        if not filename.exists() and create_if_missing:
            self.load_pip_requirements()
            with filename.open("w") as f:
                f.write(yaml.dump(self.serialized, default_flow_style=False,
                                  encoding=None))
            self.filename = filename
            return self.save(filename)
        with filename.open() as f:
            for group, requirements in yaml.load(f.read()).items():
                for requirement in requirements:
                    self[group].add(Requirement.coerce(requirement))
        self.filename = filename
def delete_forum(forum_id):
    forum = Forum.query.filter_by(id=forum_id).first_or_404()

    involved_users = User.query.filter(Topic.forum_id == forum.id,
                                       Post.user_id == User.id).all()

    forum.delete(involved_users)

    flash(_("Forum deleted."), "success")
    return redirect(url_for("management.forums"))