# Buggy code
def _prepare(self, channel):
    """Prepare context and category hierarchy."""
    self.context = self.populate_context(channel)
    self.base_dir = urlparse(self.context["BASE_URL"]).path

    if self.export_categories_as_categories:
        wordpress_namespace = channel.nsmap["wp"]
        cat_map = dict()
        for cat in channel.findall("{{{0}}}category".format(wordpress_namespace)):
            # cat_id = get_text_tag(cat, '{{{0}}}term_id'.format(wordpress_namespace), None)
            cat_slug = get_text_tag(
                cat, "{{{0}}}category_nicename".format(wordpress_namespace), None
            )
            cat_parent_slug = get_text_tag(
                cat, "{{{0}}}category_parent".format(wordpress_namespace), None
            )
            cat_name = utils.html_unescape(
                get_text_tag(cat, "{{{0}}}cat_name".format(wordpress_namespace), None)
            )
            cat_path = [cat_name]
            if cat_parent_slug in cat_map:
                cat_path = cat_map[cat_parent_slug] + cat_path
            cat_map[cat_slug] = cat_path
        self._category_paths = dict()
        for cat, path in cat_map.items():
            self._category_paths[cat] = utils.join_hierarchical_category_path(path)


# Traceback (KeyError)
########################################
TaskError - taskid:render_galleries:output/galleries/index.html
PythonAction Error
Traceback (most recent call last):
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/doit/action.py", line 360, in execute
returned_value = self.py_callable(*self.args, **kwargs)
File "/home/kwpolska/git/nikola/nikola/plugins/task/galleries.py", line 466, in render_gallery_index
self.site.render_template(template_name, output_name, context)
File "/home/kwpolska/git/nikola/scripts/../nikola/nikola.py", line 607, in render_template
template_name, None, local_context)
File "/home/kwpolska/git/nikola/nikola/plugins/template/mako.py", line 88, in render_template
data = template.render_unicode(**context)
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/mako/template.py", line 452, in render_unicode
as_unicode=True)
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/mako/runtime.py", line 807, in _render
**_kwargs_for_callable(callable_, data))
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/mako/runtime.py", line 839, in _render_context
_exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/mako/runtime.py", line 865, in _exec_template
callable_(context, *args, **kwargs)
File "/home/kwpolska/Desktop/nikola-translated-path/cache/.mako.tmp/base.tmpl.py", line 91, in render_body
__M_writer(unicode(base.meta_translations()))
File "/home/kwpolska/Desktop/nikola-translated-path/cache/.mako.tmp/base_helper.tmpl.py", line 274, in render_meta_translations
__M_writer(unicode(_link(permalink, None, langname)))
File "/home/kwpolska/git/nikola/scripts/../nikola/nikola.py", line 765, in link
return self.path(*args, is_link=True)
File "/home/kwpolska/git/nikola/scripts/../nikola/nikola.py", line 729, in path
path = self.path_handlers[kind](name, lang)
KeyError: u'/galleries/galleries/index.html'

# Fixed code
def _prepare(self, channel):
    """Prepare context and category hierarchy."""
    self.context = self.populate_context(channel)
    self.base_dir = urlparse(self.context["BASE_URL"]).path

    if self.export_categories_as_categories:
        wordpress_namespace = channel.nsmap["wp"]
        cat_map = dict()
        for cat in channel.findall("{{{0}}}category".format(wordpress_namespace)):
            # cat_id = get_text_tag(cat, '{{{0}}}term_id'.format(wordpress_namespace), None)
            cat_slug = get_text_tag(
                cat, "{{{0}}}category_nicename".format(wordpress_namespace), None
            )
            cat_parent_slug = get_text_tag(
                cat, "{{{0}}}category_parent".format(wordpress_namespace), None
            )
            cat_name = utils.html_unescape(
                get_text_tag(cat, "{{{0}}}cat_name".format(wordpress_namespace), None)
            )
            cat_path = [cat_name]
            if cat_parent_slug in cat_map:
                cat_path = cat_map[cat_parent_slug] + cat_path
            cat_map[cat_slug] = cat_path
        self._category_paths = dict()
        for cat, path in cat_map.items():
            self._category_paths[cat] = hierarchy_utils.join_hierarchical_category_path(
                path
            )